You can generally avoid détention préventive if you are able to provide good garanties de re-présentation, i.e., if you can convince the judge that even if they

You can generally avoid détention préventive if you are able to provide good garanties de re-présentation, i.e., if you can convince the judge that even if they release you, you will show up to court when asked to. These documents are generally proof of insertion in active life (having a stable job, family, etc.) that should prevent you from disappearing (e.g., in order not to lose your job). I don't know what those would be in this case. But then again, the justice system is never exactly the same for people in positions of power, as Durov is.