En réponse à Loweel.

@Framasoft and @Loweel : have a look at https://media.ccc.de/v/camp2023-57168-flohmarkt ..

This I saw first on the chaos communication camp last year, it is able to speak activity pub.

The developer lives in Berlin, but his software got already adapted by a collective in switzerland:

https://fediflohmi.ch/

In case you want to make your french version out of it, I can offer to translate - I speak german, italian and enough french to translate ( I cannot speak with people from Paris though, but understand pretty everything reading)