Accounting politicians for crimes is not a problem as long as the judicial system is sufficiently independent from the executive. It is my impression that the French justice system is more independent and better protected against the executive branch than the US justice system, but I admit that I'm not an expert on comparing the two systems and could be wrong. It's really just a hunch aggregated from what I've heard over the years.
It is looks very similar in France and in the US to some extent. I copy a post I made somewhere in this thread as I think it can help here:
Prosecutors are formally under executive control but since 2013 the justice minister should not give orders on individual cases.
France has an additional layer of independence compared to the U.S. because of the juge d’instruction (investigating judge), who is supposed to be independent from the executive like the courts judges, unlike prosecutors.
I say in principle because judges are appointed in France and not elected (similarly to federal judge in the US from what I understood). The executive as some control through appointments and career advancements but they are not supposed to use it to sanction or reward the judges.
The effectiveness of these independence mechanisms remains a subject of active debate, as evidenced by the relatively recent changes made to them.