How was charles de gaulle instrumental in defeating the germans in france?

Seriously is this a trick question? a french general defeating the Germans? hah

He wasn't. The Germans walked through France as if they were going to a picnic. De Gaulle sat it out like a whipped puppy dog. When it was all over, he asked to be permitted to put on his best uniform and ride through Paris as a conquering hero. 
The allies agreed, so de Gaulle was the big Nazi-killer. After the war, he accepted thousands of tons of food to keep his people alive ( all on the US taxpayer ). But he disagreed with anything America tried to accomplish. He was against America before he knew what the subject was. 
The gall of de Gaulle