It's not for the government to communicate, and criminal investigations are secret in France. So prosecutors don't have to make any public statements or release any documents (and in fact they shouldn't) but in such high profile cases they are likely to make a general statement to placate the media.
The man has four passports and I'm curious about how he got the French one... This is on his Wikipedia page:
"Durov was naturalized as a French citizen in August 2021, giving him European Union citizenship. Le Monde described the naturalisation as "mysterious", since Durov had not resided in France apart from brief visits. Le Monde suggested that Durov was naturalised via the rarely used "merit foreigner" procedure that is awarded directly by the French government to people viewed to have contributed exceptionally to France's international influence or international economic relations." [1]
Seems obvious that there is much more than meets the eye...