From my limited understanding the French hadn’t a clue as to proper use of armor at the outbreak of the war.
They sent their tanks into battle piecemeal instead of using them in tandem with infantry.
By their tactics they were doomed to fail.
In contrast General Patton had studied the writings of Rommel and Guderian and had a better understanding of the uses of armor with infantry in battle.
Patton said the problem with the Brits and French was they were always well prepared to fight the last war, not the new one.
That wasn’t by choice - the French intended to send their tanks into action by formations. One problem was that most French tanks didn’t have radios and once they’d encountered German blitzkrieg tactics, their main formations were broken because they were unable to change tactics or posture without radio communication between tanks. French doctrine emphasized that all operations would proceed according to a pre-arranged plan and that as no deviation was to be made from it, there was no need for radio. Just follow the plan - which, if the Germans had been so obliging as to cooperate, would have resulted in Panzer IIIs getting slaughtered by mass Somua and Char tank formations.
After reality bashed in the skulls of the plans the French had and the radio-heavy Wehrmacht scrapped their plan-bound initial opponents, the French then rushed what tanks they could up but they ended up getting to the front lines in penny packets instead of powerful formations not because they wanted to but because they needed something, anything to plug the gap and stem the oncoming tide. They simply didn’t have the time or space to marshal a tank formation and to be fair it wouldn’t have mattered if they did due to the lack of radios.
The French had an excellent grasp of the proper use of armor at the beginning of the war. What they didn’t have was a grasp of the proper unit control and strategy in an age of mobile warfare - it wasn’t just tanks that suffered from this problem. See this video, starting at about 4:38 (though the whole video is worth watching) for more info: https://www.youtube.com/watch?v=hGpdXRaILe0
The presenter is an armor officer who served in the Irish Army and in combat in the Sandbox in the US Army in the Abrams.