During the 20th century, the Communism Party and the "CGT" syndicate started to gain huge influence in all those state-owned Arsenals. The tradition of centralization is very old in France, and the difference between "Colbertism" and "Communism" is thin.
So, to keep a long story short, those Arsenals were nearly governed from Moscow, with acts of sabotage during WWII and during all "low intensity" conflicts afterwards (Indochina, Algeria...). Add a very, very advantageous status of the "Ouvriers d'Etat" (life employment, retirement at 55 years, huge pension...) combined with the complete unreliability of those state-owned manufactures, and the politics were in search of the first opportunity to close them.
During the '90s, the Communist Party was highly active in the reduction of defence budgets, and the other parties agreed that closing those manufactures was a way to reduce the defence budget AND reduce the influence of the CGT / Communism Party.
The capability to equip troops with a domestic rifle was considered less important than being still able to deploy nuclear weapons
в общем, это злые комуняки со времен Луи 14го виноваты в том, что французы просрали свою промышленность по производству стрелкового оружия.