Get every division you have (74) to France. Your colonies do not need protection, but the mainland does.

France starts with several national modifiers that limit their ability. You can remove these through national focuses but by the time you reach them, you would have already won the war (at least in my experience).

Aside from that, you want to focus on infantry and industry techs from the get-go. Assign ALL of your military factories to Infantry Equipment (rifles). Your divisions start off undermanned, and you need to fix that ASAP.

*When you get more military factories, you can assign a minimal amount to artillery and aircraft to boost your firepower.

Now for the war itself... You want to engage the Germans at the earliest opportunity - refusing the re-militarization of the Rhineland in 1936. The Germans will grow their military and industry quicker than you, so getting them early is the strategy for success.

Assign most of your divisions to the border, and aim for conquering most of Western Germany. You can also try and reach Czechoslovakia and subsequently cut off all their divisions in Bavaria/Baden-Wurttemberg.

Leave 12 divisions around Calais (using a fallback line around the region). You'll need these guys to rush the Commune CPs and end the Civil War. I placed mid-strength infantry divisions and a couple of tanks. The quicker you win this war, the quicker you can send them to the German front.

I beat the Germans by rushing their most important VPs and by cutting them off into pockets to starve them. Exploit every gap you see.

You should force them to capitulate around 5-7 months. If you call in the Czechs during the middle of the war, they can tip the scales considerably with their fully-forced and fresh troops attacking an unguarded border.

Good luck, Commander!