All secured OSes and messaging systems are threatened by European governments / EU institutions at the moment, and the French government has been doing so for a few years.

This is not a grapheneOS only issue and it is not new.

From France: news outlets began parroting government stating GrapheneOS is used by narcos.

GrapheneOS reacted strongly.

However, France is on a very shitty auth-right trend (including arresting Telegram founder) so the reaction is very understandable.