Yes, most of Europe/the World uses a "civil law" system which is much less adversarial than the U.S. & U.K.'s "common law" system.[1]

Fun fact: because of their French (and to a lesser degree, Spanish) influence, Louisiana's laws still follow a civil law system.

[1] https://www.apprendre-le-droit.fr/anglais-juridique/what-is-...

And yet Louisiana has one of the highest (if not the highest) rate of incarcerations per-100k in the country[0]. Perhaps ‘less adversarial’ doesn’t count for much when it comes to the business end of the law.

[0]https://en.m.wikipedia.org/wiki/List_of_U.S._states_by_incar...

Since most European countries (civil law systems) don't have such high incarceration rates and considering the U.S. (common law system) has one of the highest I don't think it's fair to attribute Louisiana's high incarceration rate to the state's civil law system.

Louisiana is one of the poorest states in the country and has one of the highest contracted private prison quotas in the country (96% occupancy).[1] And until recently, Louisiana had some of the harshest mandatory minimum drug sentencing requirements.[2] They still have harsh mandatory minimums for other offenses. If you're looking for an explanation for Louisiana's criminal justice issues those factors are the far more likely explanations than the existence of a civil law system.

[1] https://en.m.wikipedia.org/wiki/Louisiana_Department_of_Publ...

[2] https://www.pewtrusts.org/-/media/assets/2018/03/pspp_louisi...