Probably because no one talks about it.
Corruption is largely a taboo issue in France. Neither government nor independent researchers have conducted any comprehensive and empirically based analyses of the phenomenon in the recent past. In addition, the French government does not report publicly on organised crime, and academic research is very limited. The information available publicly nevertheless provides sufficient evidence that in certain geographic (Corsica, large cities, or South-Eastern France) or economic areas (public utility contracts, energy, real-estate, or defence sectors) corruption is often encountered. At the lower level of organised crime, police (information leaking, or direct involvement in OC activities) and local authorities (regarding public contracts) are most often targeted by criminals. At the higher level, judicial corruption and undue political influence over the criminal justice process occur in relation to financial and corporate crimes. The scale of the corruption problem remains unclear due to lack of data. In Corsica, parliamentary reports indicate that the problem is commensurate with the one in mafia-affected regions of Italy.
https://ec.europa.eu/home-affairs/sites/homeaffairs/files/do...