Answer
**Imprisonment was Léon M'ba's punishment for his political activism.** During his time as a government employee and a civil servant, M'ba was an avid supporter of Gabonese independence. His political activism did not go unnoticed by the French colonial administration, and as a result, he was detained. M'ba's imprisonment served as a symbol of the French colonial government's suppression of Gabonese nationalists and their aspirations for self-determination.