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Introduction

In this guide, you’ll learn how to issue invoices to French public institutions using Chorus Pro. It will walk you through:
  1. Understanding Chorus Pro and its format requirements
  2. Setting up Invopop workflows:
    • Supplier registration workflow
    • Invoice submission workflow
  3. Preparing the Chorus Pro platform and creating credentials
  4. Registering a supplier with Chorus Pro
  5. Submitting your first invoice to a French public institution

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What is Chorus Pro?

Chorus Pro is a mandatory service provided by the French government for invoicing French public institutions. The platform allows businesses to upload invoices in multiple e-invoicing formats and track them throughout the French public administration process. All invoices to French public sector entities must be submitted through Chorus Pro. The platform supports various e-invoicing formats including Cross Industry Invoice (CII), and implements the European Norm 16931 (EN16931) European standard for electronic invoicing with additional French-specific requirements.

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Understanding Chorus Pro Format Requirements

Chorus Pro accepts invoices in CII format based on the EN16931 European standard. However, it adds specific French extensions and validation requirements: EN16931 Standard The EN16931 defines the semantic data model for electronic invoices. The standard ensures interoperability across European Union (EU) member states while allowing for country-specific extensions. Chorus Pro Extensions Chorus Pro extends the base EN16931 standard with additional French requirements:
  • SIRET number validation for French entities
  • Specific invoice types for different purposes
  • Service codes for government departments
In GOBL, these formats are handled via addons that you must add to each invoice. You’ll see examples of this further below.

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Setup

Configure your Invopop Workspace for Chorus Pro invoicing. Complete these steps:
1

Connect the required apps

  1. Go to Configuration > Apps in the Console.
  2. Find UN/CEFACT CII in the app list and click Connect to activate the app.
  3. Find Chorus Pro in the app list and click Connect to activate the app.
After connecting, you’ll see both UN/CEFACT CII and Chorus Pro listed in the Enabled Apps section.
Chorus Pro app connected
2

Configure the supplier registration workflow

Add a new workflow to your workspace for registering suppliers. You can start with the template below.Keep the workflow ID at hand as you’ll need it later.
3

Configure invoice workflow

Add a new workflow to your workspace for issuing invoices. You can start with the template below.Keep the workflow ID at hand as you’ll need it later.

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Chorus Pro Credentials

This section explains what suppliers need to configure within their Chorus Pro account to enable integration with Invopop. To configure Chorus Pro, complete these steps:
1

Create a Chorus Pro account

Sign up for a Chorus Pro account if you don’t have one.
To test in sandbox mode, create an account in the Chorus Pro sandbox. Download a CSV file with test accounts. Use one of the accounts to log in. For more information, visit the Chorus Pro documentation.
2

Navigate to API settings

Once logged in to your Chorus Pro account, navigate to the API configuration area:
  1. Go to Domains > Connections in the main menu
Navigate to Domains → Connections

Navigate to Domains → Connections

  1. Click Access Service in the Technical Account section (bottom left)
Navigate to Technical Account

Navigate to Technical Account

This opens a new page where you can manage your technical accounts.
3

Create a technical account

Set up the technical account credentials, this opens a form to create a technical account:
  • Set the type of request to Creation of a technical account
  • Select your company in the company field
  • This creates a login and password. Copy these credentials as you’ll need them when registering with Invopop
    Technical Account Creation

    Technical Account Creation

Click Submit to complete the setup
Return to Invopop for the next steps.

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Running

Now you’ll learn how to register a supplier and issue Chorus Pro invoices:

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Register a Supplier

Now that you have a technical account, you can register a supplier with Chorus Pro.
1

Upload a Supplier

Use the Create an entry endpoint to upload a new supplier. Include a party object in the data field. For this step, you only need the VAT number.After successful upload, you’ll see the supplier in the Contacts section with status Empty.
Supplier registration in progress

Supplier registration

2

Send the Supplier to the registration workflow

Send the supplier to the registration workflow using the Create a job endpoint. Use:
  • The supplier’s silo entry UUID from the previous step
  • The Supplier Registration workflow ID from the Setup section
This workflow generates a unique URL for the supplier to access and complete the registration process. The URL is stored in the supplier’s metadata.
Supplier registration in progress
3

Complete Chorus Pro Authentication

The workflow stays in progress until the supplier completes the registration process. The supplier must access the link and add the credentials they created previously.
Supplier registration in progress
The supplier’s status will change to Registered when authentication is complete.
You can fill the form via API by sending a PUT request to the registration link. The payload should be a JSON object with the following fields:
  • username (string): The supplier’s Chorus Pro username.
  • password (string): The supplier’s Chorus Pro password.

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Send an Invoice

Once a supplier is registered, you can send invoices to French public institutions through Chorus Pro.
1

Create an Invoice

Use the Create an entry endpoint to create a new invoice. Include an invoice object in the data field.
Chorus Pro B2G Invoice
{
	"$schema": "https://gobl.org/draft-0/envelope",
	"head": {
		"uuid": "8a51fd30-2a27-11ee-be56-0242ac120002",
		"dig": {
			"alg": "sha256",
			"val": "4dde30dddc3c585d881c399680842e7167a5619457fc27cf84ca48c22b41af45"
		}
	},
	"doc": {
    "$schema": "https://gobl.org/draft-0/bill/invoice",
    "$regime": "FR",
    "$addons": [
        "eu-en16931-v2017",
        "fr-choruspro-v1"
    ],
    "uuid": "019783e7-33b1-7000-a1a5-6139e214b447",
    "type": "standard",
    "series": "SAMPLE",
    "code": "2345",
    "issue_date": "2025-06-18",
    "currency": "EUR",
    "tax": {
        "ext": {
            "fr-choruspro-framework": "A2",
            "untdid-document-type": "380"
        }
    },
    "supplier": {
        "name": "Provide One Inc.",
        "tax_id": {
            "country": "FR",
            "code": "43498927917"
        },
        "identities": [
            {
                "type": "SIRET",
                "code": "49892791768734"
            }
        ],
        "addresses": [
            {
                "num": "42",
                "street": "Calle Pradillo",
                "locality": "Madrid",
                "region": "Madrid",
                "code": "28002",
                "country": "ES"
            }
        ],
        "emails": [
            {
                "addr": "billing@example.com"
            }
        ],
        "ext": {
            "fr-choruspro-scheme": "1"
        }
    },
    "customer": {
        "name": "Sample Consumer",
        "tax_id": {
            "country": "FR",
            "code": "39356000000"
        },
        "identities": [
            {
                "type": "SIRET",
                "code": "35600000012345"
            }
        ],
        "addresses": [
            {
                "num": "1",
                "street": "Rue Sundacsakn",
                "locality": "Saint-Germain-En-Laye",
                "code": "75050",
                "country": "FR"
            }
        ],
        "emails": [
            {
                "addr": "email@sample.com"
            }
        ],
        "ext": {
            "fr-choruspro-scheme": "1"
        }
    },
    "lines": [
        {
            "i": 1,
            "quantity": "20",
            "item": {
                "name": "Development services",
                "price": "90.00",
                "unit": "h"
            },
            "sum": "1800.00",
            "discounts": [
                {
                    "reason": "Special discount",
                    "percent": "10%",
                    "amount": "180.00"
                }
            ],
            "taxes": [
                {
                    "cat": "VAT",
                    "rate": "standard",
                    "percent": "20%",
                    "ext": {
                        "untdid-tax-category": "S"
                    }
                }
            ],
            "total": "1620.00"
        }
    ],
    "payment": {
        "advances": [
            {
                "description": "Paid in full",
                "percent": "100%",
                "amount": "1944.00"
            }
        ],
        "instructions": {
            "key": "card",
            "card": {},
            "ext": {
                "untdid-payment-means": "48"
            }
        }
    },
    "totals": {
        "sum": "1620.00",
        "total": "1620.00",
        "taxes": {
            "categories": [
                {
                    "code": "VAT",
                    "rates": [
                        {
                            "key": "standard",
                            "ext": {
                                "untdid-tax-category": "S"
                            },
                            "base": "1620.00",
                            "percent": "20%",
                            "amount": "324.00"
                        }
                    ],
                    "amount": "324.00"
                }
            ],
            "sum": "324.00"
        },
        "tax": "324.00",
        "total_with_tax": "1944.00",
        "payable": "1944.00",
        "advance": "1944.00",
        "due": "0.00"
    }
	}
}
Review the example above. Notice that you need both the eu-en16931-v2017 and the fr-choruspro-v1 addon. These addons enable all the necessary validations in your GOBL invoice.
1

Send to Chorus Pro

Send the invoice to Chorus Pro using the Create a job endpoint. Use:
  • The invoice’s silo entry UUID from the previous step
  • The Chorus Pro Invoice workflow ID from the Setup section
The system generates a CII XML file with Chorus Pro extensions and submits it to the platform.
Invoice sent to Chorus Pro
2

Track Invoice Status

After submission, track your invoice in Chorus Pro using the invoice identifier (series plus code).
Chorus Pro allows document modifications after submission. If a document is rejected or contains errors, update the GOBL details and resubmit to the same workflow until the document is accepted. Once accepted, do not modify the invoice.
The invoice identifier in Chorus Pro corresponds to your GOBL invoice series and code combined. This identifier helps you locate and track invoices across both systems.

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FAQ

Chorus Pro primarily supports CII format based on EN16931. Invopop currently focuses on CII with plans to add additional formats in the future.
French businesses need a SIRET number. Foreign businesses can use their local tax identifier, but should verify acceptance with the receiving French institution.
Yes, you can modify and resubmit invoices until the receiving institution accepts them. Once accepted, invoices become locked and cannot be modified.
Use your GOBL invoice series and code combined as the invoice identifier in the Chorus Pro portal to locate your submitted invoices.
Ensure the supplier has a valid Chorus Pro account and provided correct credentials. Contact support if registration workflow issues persist.
Chorus Pro has specific file size and format requirements. Invopop handles these automatically when generating CII XML files from your GOBL invoices.