does F-Secure support being installed on a Freebox (in France) or other similar Internet boxes ?
Sorry for my reply. I'm only an F-Secure user (their home solutions). So, it is only my own unofficial feelings.
I think that: "no".
but maybe some clarifications are needed:
-> did you mean possibility to install F-Secure SAFE (?) on a "Freebox"?
-> or something else?
In general, there are requirements for F-Secure SAFE:https://community.f-secure.com/t5/F-Secure-SAFE/What-are-the-system-requirements/ta-p/77885
it should be possible to install on devices with noted platforms.
Most likely that Freebox with another OS (specific for such solution).
Or your ask is about potential F-Secure solution for such devices?