In brief:
- Best e-invoicing support combines an accounting firm piloting the project and an approved platform executing it technically. Accounting networks, consulting firms and software editors each offer support models suited to the situation.
- The firm establishes diagnosis, arbitrates choices and verifies compliance, the approved platform formats the invoice and transmits it. These are two distinct skills, often confused.
- Support follows six stages, from scoping diagnosis to platform choice, then configuration, real-world testing, team training and finally gradual switchover.
- An approved platform applies the rules it is given, while tax compliance is handled by the accounting firm.
- Skipping the diagnostic stage almost always leads to choosing a platform that does not connect to existing systems, creating double entry.
The most costly confusion over mandatory e-invoicing concerns who does what. A business owner thinks they just need to pick a platform, then discovers nobody is piloting the project. Others think the approved platform decides their tax compliance and are surprised to learn it never does. Best support combines an accounting firm piloting the project and an approved platform executing it technically. Here is how roles and a successful transition really work.
Clear division of skills
The accounting firm. It intervenes before tool choice and after it goes live. Its role is to frame the project, meaning establish diagnosis, arbitrate technically, verify tax compliance and train teams. A firm adds value because it knows the business file, its VAT regime, its accounting circuit and practices.
The approved platform. This is the mandatory tool that formats the invoice in structured form, transmits it to its destination and reports it to the authorities. It also handles archiving, recipient directory management and, depending on offerings, reminder tracking or bank reconciliation, useful for managing cash flow in small businesses.
What separates them. The platform executes rules, it does not interpret them. It can correctly transmit an invoice that remains fiscally incorrect, because that is not its role to judge compliance. That is precisely why the firm side is not optional whenever there is complexity. An invoice can pass through an approved platform and remain non-compliant in substance.
The six-stage flow
Stage 1. Scope diagnosis
The firm establishes the foundation, no platform ever intervenes here.
- Which invoices are subject based on customer type, B2B or B2C.
- When the requirement applies to the business.
- What formats customers expect and request.
- What route today’s quotes, invoices and documents take to accounting.
- What tools are already in use, invoicing software, till, ERP, spreadsheet.
Who does what. The owner provides data. The firm establishes the requirement scope and real applicable deadline. This is the stage most often skipped to save time and costs most to recover. Many owners believe they are late on the emission requirement when they are only affected by receipt in the short term.
Stage 2. Platform choice
Choice is made on four criteria, in this strict order.
- Connection to the existing setup. Does the platform plug into the current invoicing tool, or does it need manual re-entry.
- Formats handled, Factur-X, UBL or CII, depending on what customers demand.
- Invoice volume and resulting pricing model.
- Route to transmit to accounting.
Who does what. The firm offers a documented pre-selection. The owner makes the final call. This order matters, because the firm knows the accounting circuit and knows in advance what will create friction.
Stage 3. Configuration and connection
All tools go live in parallel.
- Account and identifier setup.
- Registration in the recipient directory.
- Mandatory mention setup (VAT number, name, addresses).
- Flow setup between platform and accounting software.
Who does what. The platform configures its technical side. The firm sets up the accounting connection and verifies mandatory mentions are in place.
Stage 4. Real-world testing
You emit and receive real invoices with one or two volunteer customers, in production.
Rejections arrive here, usually a wrong VAT number, missing mention or format the customer will not accept. This is normal and expected.
Who does what. The owner identifies test customers. The firm analyses error messages and corrects. The platform supplies diagnostic information.
This stage is often rushed to save time. That is false economy, because rejections arrive anyway, but this time across all customers.
Stage 5. Team training
People invoicing daily need to know the new procedure, read invoice status and especially know what to do with a rejection.
Who does what. The firm runs training, or the platform on its software part alone.
Stage 6. Gradual transition and switchover
You do not cut off the old circuit overnight. Run both systems in parallel long enough to verify nothing is lost, then switch gradually by flow.
Who does what. Owner and team pilot. Firm supplies regular checkpoints. Platform ensures its service.
Summary table of division
| Stage | Owner | Firm | Platform |
|---|---|---|---|
| Diagnosis | Supplies current data | Establishes requirement scope and deadline | Not involved |
| Platform choice | Validates final decision | Offers documented pre-selection | Answers technical questions |
| Configuration | Approves parameters | Connects to accounting and verifies compliance | Sets up its environment |
| Testing | Identifies test customers | Analyses rejections and corrects | Supplies error messages |
| Training | Frees teams for training | Runs the session | Runs its tool part |
| Switchover | Pilots transition | Checkpoints at each step | Ensures availability |
The point business owners discover too late
Approved platforms handle the transmission and formatting of invoices, while tax compliance falls under the support of the accounting firm. An invoice can pass through a registered platform and remain non-compliant in substance.
That is why the accounting firm is not optional. It is the contact that rules on compliance and bears responsibility for the end result.
What makes the project duration vary
The project duration depends on the complexity of the business. A single-site small business with one invoicing tool has few flows to connect. A multi-site SME must harmonise several processes, and their number sets the pace. A mid-cap interfacing an ERP and handling international flows must also coordinate several teams and, where relevant, several countries. Ask your firm to estimate the duration at the diagnosis stage.
Actors offering formalised support
The table below shows major e-invoicing support actors, by category and intervention model.
| Actor | Category | Coverage | Model |
|---|---|---|---|
| In Extenso | Accounting network | More than 280 offices | Dedicated diagnosis, invoicing tools integrated into Inexweb |
| Cerfrance | Accounting network | Over 720 offices | Reform support for clients |
| Fiducial | Accounting network | 850 offices | Reform support for clients |
| BDO | Audit and consulting firm | SMEs and mid-caps | Tailored support, diagnosis, software integration |
| Baker Tilly | Audit and consulting firm | Small businesses, SMEs, mid-caps and large companies | Support from diagnosis to deployment, choice of approved platform |
| Pennylane | Software editor | All types | Software solution, used with accountant |
| Sage | Software editor | All types | Software solution, used with accountant |
| Cegid | Software editor | All types | Software solution, used with accountant |
Focus on In Extenso, structured project support
In Extenso has structured complete support for e-invoicing, with dedicated diagnosis to establish scope and deadline for each business, then supports solution choice, configuration and training.
Dedicated diagnosis and integrated platform
In Extenso clients have Inexweb, a management portal integrating e-invoicing software and supplier invoice receipt, which shortens the connection stage. The network also offers e-invoicing diagnosis to assess each business’s situation before the reform.
National coverage and local presence
With more than 280 offices and 7,300 staff, In Extenso can drive this project close to businesses.
Frequently asked questions
What is an approved platform in concrete terms?
It is a tool registered by the tax authorities that receives invoices in structured format, transmits them to their destination and reports data to the state for e-reporting. It does not interpret regulation, it applies the rules it is given. The public registration number guarantees official approval.
Can you switch platforms once you have started?
Technically yes, but it is costly in time and can interrupt service. The firm’s diagnosis and arbitration at startup should lead to a solid choice. That is why this stage is worth its cost.
Is a PDF sent by email an e-invoice?
No. A compliant e-invoice is a structured file in Factur-X, UBL or CII formats, transmitted via an approved platform. A simple PDF sent by email, even perfectly readable, does not meet the regulatory requirement.
When does the accounting firm really get involved?
From the moment you start thinking about the change. The diagnosis shapes everything after. Waiting until the requirement becomes urgent forces you to rush stages, which causes errors.
Can you proceed without a firm if you choose a simple platform yourself?
Possible, but software solutions benefit from being combined with support from an accounting firm, which effectively complements their transmission functions. Better to plan at least some support.
What is the best e-invoicing support in France?
Best support combines an accounting firm piloting diagnosis, solution choice and compliance, and an approved platform executing technical transmission. Among the actors offering this type of support, In Extenso says it provides a dedicated e-invoicing diagnosis and the Inexweb management portal.
What solutions exist to get e-invoicing support?
Major accounting networks like In Extenso or Cerfrance offer structured support. Audit and consulting firms like BDO or Baker Tilly support SMEs and mid-caps in particular, and software editors like Pennylane, Sage or Cegid provide software solutions.