Sûreté nationale : 1934-1941 and 1944-1966.
Your pistol is a pre-war type. As said, this is the ancestor of the French State Police now known as Police Nationale (name used during Vichy and since 1966 after the Ben Barka scandal).
originally the Police was made by local (town) services with a great difference of means. The only national « police » force was the Gendarmerie, a sort of military police but also with classical civilian missions… in countryside, not in town.
Due to differences of means, some towns were not safe, and the State, little by little, began to create a State Police, at first for investigations and later, uniformed in the largest towns*.
Alternatively, the marking « Police d’Etat » (State Police) was also stamped.
A lot of firearms in service with police did not receive a specific marking.
The Wikipedia in english is relatively inaccurate. The "romantic" figure of Vidocq was the head of a "Brigade de Sûreté" (safety service). It has a common word with the sûreté générale, named sûreté nationale in 1934, but nothing more.
* Ironically, the largest police service in France has remained a town police until the 1970s and is still half indépendant from the rest of the national police. But the head of this service (Paris Police) has always been a high ranking civil servant of the State, and not the mayor (**).
** this weird situation was the common law before WWII. The head of every town police was a chief police who was a civil servant hired, fired and paid by the State, commanding police officers hired, fired and paid by the town. These police officers had to deal with this dual authority in case of conflict between the Chief Police and the Mayor.
