Is sexist behavior always grounds for dismissal?

Mr. [S] was hired as a senior technician on September 21, 1993 by the public technical and industrial establishment Commissariat à l’énergie atomique et aux énergies alternatives (CEA).

On September 1, 2016, he was given a precautionary layoff and summoned to an interview prior to possible dismissal, then to appear before the conventional council, to which the employer submitted a proposal for a one-month layoff.

Dismissed for misconduct by letter dated October 11, 2016 for making inappropriate comments with sexual connotations about female colleagues, the employee brought an action before the industrial tribunal to contest the termination.