Because France was not Hitler's primary goal. While Hitler did indeed possess great resentment over the treatment of Germany at the end of the First World War and France's occupation of certain German territories, France was a stepping stone to Hitler's and the Nazi Party's ultimate froeign-policy goal, Lebensraum, or 'living space' in English.

Hitler laid out his foreign policy goals in Mein Kampf, in fact he wrote an entire chapter about it: Eastern Orientation or Eastern Policy. This chapter called for an eastern expansion of Germany's borders with the goal of clearing territory of Slavic inhabitants and colonising those regions with Germans. If you look at the beginning of the Second World War, you can see that Germany's military strategy was orientated to the east, directed at Czechoslovakia and then Poland. Hitler knew that he would have to fight France, German hostility was not going to go unchallenged by the west and France possessed the largest land army and most armoured vehicles (though quite a few of these were First World War Renaults). For Hitler and the Nazi party to accomplish their goals in the east, they needed to secure their western flank and that required the invasion of Holland, Belgium and France and ultimately led to the Fall of France.

Ironically, the defeat of France and the capture of so much mechanised material such as trucks and tanks aided the Germans in 1941 when Operation Barbarossa was launched.

Source:

Mein Kampf by Adolf Hitler

The Second World War by Antony Beevor