1. Immediate answer: identify the first live population and its owners
France's electronic invoicing reform took effect on 1 September 2026, according to the Service-Public update published on 2 September. From that date, all businesses affected by the reform must be able to receive electronic invoices. Large enterprises and entreprises de taille intermédiaire (ETIs) also began issuing electronic invoices and performing applicable e-reporting on 1 September 2026; SMEs and micro-enterprises follow for issuing and e-reporting on 1 September 2027. A group should assess the obligation legal entity by legal entity rather than infer it from a parent company's size or a software setting. Tax should confirm scope, finance should own the control totals, data or IT should evidence the interfaces, and an accountable period owner should decide whether the pack is ready for sign-off. E-reporting is not the same flow as domestic B2B e-invoicing. Domestic B2B invoices within the reform's scope travel through a registered plateforme agréée (PA) as electronic invoices. E-reporting covers required transaction data for transactions outside that domestic B2B e-invoice lane, notably relevant B2C and international B2B activity, plus payment data in the applicable VAT-on-receipt cases. The August 2026 DGFiP sheets describe different levels of aggregation and different payment treatment for those populations. Only a registered PA can transmit regulated invoice, transaction and payment data to the administration; an ERP or connector may prepare data, but it does not replace that regulated role. Nor does e-reporting replace ordinary bookkeeping, VAT controls, supporting documents or the VAT return process. It creates another governed output that must be traceable to sales, cash and accounting evidence. The practical first-period question is therefore not simply, 'Did the PA show green?' It is: did the frozen source population contain every applicable record and no excluded record; did transformation preserve the right period, category, VAT rate, amount and identity; did the PA receive the intended version; and is every final outcome or open exception evidenced? On 7 September 2026, the first normal-monthly transaction period, 1–10 September, is still open. Teams can map scope, test extracts, agree control keys and collect evidence now, but they should not describe that period as complete or sign a final submission today. A temporary transmission difficulty should not halt business activity: DGFiP's practical launch guide distinguishes data that exist but cannot be transmitted from data that are not produced correctly. Preserve business records and incident evidence, avoid knowingly sending manifestly wrong data, and route each issue to controlled correction or transmission. This operational guide is practical information, not legal, tax or accounting advice.