The project is small next to the Microsoft 365 estates most WindowsForum readers manage. It still gives a clear picture of how a public body leaves a US collaboration platform in stages. The organisers start with the easiest workload, run it on infrastructure they control, and treat identity, directories and interoperability as the hard parts. They also say openly that Teams comes later.
The Matrix Federation Gives French Councils an Alternative to WhatsApp
Computer Weekly reported the rollout on September 25, 2026. It describes a WhatsApp-style messaging service based on the Matrix open source protocol that four French local authorities have trialled and that will become available to local authorities across France from January 2027. The pilot participants were Sitiv, a digital-service provider for local authorities in the Rhône basin, along with the municipality of Échirolles near Grenoble, the city of Montpellier and the city of Strasbourg.
Other sources set the timeline a little earlier. The trade publication Acteurs Publics reports that territorial digital operators and associations of elected officials officialised, on 14 September 2026, the Fédération Matrix des collectivités. Smart City Mag gives the same launch date. ADULLACT, the association that promotes free and open-source software in French local government, says the federation is already in its deployment phase and can now take in new local authorities, which can contact ADULLACT to join. The two accounts fit together: the federation exists and is accepting members now, and January 2027 is when Computer Weekly says it opens to local government nationwide.
The idea goes back further. Localtis, the local-government news service of the Banque des Territoires, reported in March 2026 that the project started in October 2025 and was presented publicly at Échirolles on February 17, 2026. ADULLACT's own records show more than 100 open-source participants meeting on October 28, 2025 at a Numérique en Commun event, where the idea took shape.
The partners are ADULLACT and Déclic. Déclic is the federation of public digital-service operators, known in French as OPSNs (opérateurs publics de services numériques). On the vendor side, Element supplies Element Server Suite Pro, and the French open-source integrators Arawa and Teamnet do the deployment work. Element's own announcement says Arawa will deploy Element inside its customers' own environments.
Why Tchap Left French Local Government Without a Secure Messenger
The French state already runs a Matrix messenger. Tchap was built by DINUM, the interministerial digital directorate, and went live in 2019. Computer Weekly says it has more than 400,000 monthly active users across central government, where its use became mandatory in 2025. Citing DINUM figures, Smart City Mag reports more than 800,000 registered agents and around 400,000 active users.
Tchap was not available to local authorities. ADULLACT director Matthieu Faure told Smart City Mag that Tchap is reserved for central administration, so local authorities cannot rely on it. Localtis reported the same limit. That left mayors' offices, departmental councils and the operators serving them using whatever was on staff phones, which in practice often meant WhatsApp. Localtis says reliance on foreign messaging tools, including WhatsApp, Telegram and Signal, is increasingly seen as a problem in the current geopolitical climate.
Faure described the plan in stages. "We want to let the local governments use something that is digitally sovereign. So to stop using WhatsApp is the first target," he told Computer Weekly, adding: "The second target is Microsoft Teams."
He also gave Computer Weekly the political background. US sanctions against the International Criminal Court in 2025 led Microsoft and other US companies to cut services to French ICC judge Nicolas Guillou and other court officials. Guillou was left unable to use Microsoft services, shop online or use apps such as Uber, PayPal and Airbnb. Faure said the episode "sounded a wake-up call for a lot of local government organisations". This is his explanation of why interest grew faster. The project itself dates from 2025 planning work.
How a Closed Matrix Federation Differs From WhatsApp and Teams
Matrix is an open, standardised messaging protocol. Its reference client is called Element. Localtis describes Matrix as a federated design in which each organisation hosts its own "instance" on its own servers. Échirolles' head of information systems, Philippe Le Brouster, lists the benefits as a distributed network with no central point, end-to-end encryption, mobile and desktop support, and sync across devices.
The French federation is not open to everyone on the Matrix network. Element describes the result as a closed (as in, private) Matrix-based Federation for Local Governments. According to Smart City Mag, unlike the public Matrix network, the federation's is closed and reserved for identified territorial actors. Localtis reported that access is restricted to local authorities and OPSNs able to manage their own instance.
The operating model is flexible. ADULLACT's project page says each member keeps control of its infrastructure by relying on its own staff, an OPSN, or a service provider. An earlier ADULLACT description says smaller territories can be supported through a shared service run by ADULLACT or by providers, so they can scale up gradually as their technical capacity allows. Déclic's network of about 80 OPSNs, as counted by Localtis, is the obvious route for small communes that have no in-house IT.
Hosting is the main difference from both WhatsApp and Teams. Element says French authorities will be able to keep their communications data on their own infrastructure, and under their own control, instead of depending on a cloud platform operated in another jurisdiction. Computer Weekly gives the same data-location reason for Tchap. The federation also has a trust model. ADULLACT describes different trust levels depending on the technical and organisational guarantees each member has in place. Smart City Mag says these levels are meant to let users tell whether they are talking to an elected official, an employee, an IT director or an outside contractor.
ADULLACT says the project has signed a long-term support (LTS) contract intended in particular to guarantee the availability of security updates. Anyone who has watched an unpatched self-hosted server go stale will see why that matters. Security-update support needs a contract behind it.
The Pilot Found Gaps in Identity, Directories and Guest Access
The most useful part of the Computer Weekly report is what went wrong in the small pilot, because these are the same problems any organisation runs into when it moves chat off a hyperscaler.
The first was identity assurance. Participants needed to verify who they were messaging and what security level that person had, so they knew what information they could share. The chosen fix is to link the service to ProConnect, France's professional identity service. ProConnect lets civil servants and private-sector employees use one professional identity to access online government services. It is a sign-in and identity layer and does not carry messages itself. ADULLACT's earlier project page lists ProConnect integration as possible "depending on the configuration level", which suggests not every member will have it on day one.
The second gap was directories. Staff needed to find people in neighbouring authorities as well as in their own. "We didn't think about it at the beginning of the project," Faure admitted. ADULLACT and Sitiv have put €100,000 into Element's technology to build a "federated directory" for finding employees in adjacent areas. No completion date has been given.
The third gap was outside participants. Another upgrade will let authorities invite non-government people, such as contractors, into private chat rooms. The published reporting does not say how those guests will be authenticated or how their access will be limited. Teams administrators used to guest access policies and Entra ID B2B controls should expect this area to be less mature at launch.
Connecting to Tchap is still work in progress. Computer Weekly says the work is under way, and ADULLACT describes it as an interconnection that will come in time. ADULLACT's earlier page says one intended use is secure exchanges with state services, including prefectures. Localtis reported in March that talks with DINUM were ongoing and noted that the security stakes of bridging the two networks are considerable. Until that link is live, a council on the federation cannot simply message a ministry on Tchap.
Microsoft Teams Is the Stated Next Target, Not the January 2027 Deliverable
For IT teams running Microsoft 365, the timeline matters most. Faure told Computer Weekly: "We just wanted to begin with text and voice message, and in the next step, we may deploy the video aspect. We wanted to do it one step at a time." Video and meetings, which Teams is mostly used for, are a possible later phase. The January 2027 service replaces the WhatsApp group chat and does not cover the Teams meeting.
The cost case is also long-term. ADULLACT accepts that Matrix is unlikely to save money straight away and says savings will come over time. Faure argues that software costs from Microsoft and other large suppliers rise every year and are unsustainable. "The money issue is a strong driver to move to something new," he said. The published reporting includes no figures, budgets or price comparisons, so this is a stated motive and not a demonstrated saving.
Adoption forecasts come with similar caveats. Faure expects gradual uptake and suggests that, if it follows the pattern of other open-source projects, half of French local authorities could be on Matrix within five years and 80% within a decade. These are projections, and no method has been published.
The migration advice may be the most transferable part of the story. Faure warned that "if you go for big bang, this is a failure for sure". He recommended finding enthusiastic early users who can help colleagues who "simply do not care". Arawa project manager Erik Da Silva estimated that moving a typical local authority to Matrix takes about three months, and he also argued for a progressive transition over a sudden switch of tools. Faure acknowledged that "in some territories there is high addiction to Microsoft".
What this means for you
If you work in or for French local government, you can join the federation now through ADULLACT. You will need to choose between running your own homeserver, using an OPSN, or buying a managed deployment from an integrator such as Arawa or Teamnet. If you administer Microsoft 365 anywhere else, nothing changes today. The project is still a useful model for scoping a messaging workload that stays under your control.
The planning questions follow directly from the pilot's findings. Before anyone mentions replacing Teams, work out where the homeserver runs and who patches it. Decide which identity provider backs sign-in, which in France means ProConnect. Plan how staff will find people in partner organisations, how guests get in and out, and whether you can bridge to the networks your counterparts already use. The French project had to add several of these after the pilot started.
France's local authorities are moving off US platforms in the order that is easiest to deliver. They start with the insecure consumer messenger staff already rely on, and they keep the data on infrastructure they control. Teams is openly planned as a later phase that depends on video support that has not been built yet. The federation opens nationally in January 2027, and the link to Tchap will decide whether councils and the state can finally message each other on one sovereign network.