Germany didn't see France as it's main threat at that time. If anything it was the French who wanted to get revenge against the Germans for what happened in 1870. The German's main rival on the world stage was Great Britain. But what the German's saw as their biggest threat was Russia. The whole reason Germany moved against France was because of the treaty between France and Russia. The alliance between these two countries meant that Germany had two potential enemies on both it's eastern & western borders. To the Germans, the French were simply in the wrong alliance. Had France not been treaty bound to go to war to aid Russia, WWI as we know it would have probably never happened.

Germany felt surrounded which for all intents and purposes, they were. Thus is what lead the Germans to come up with the Schlieffen Plan. Basically the plan called for knocking France out of a war in a campaign lasting about 6 weeks before the Russians could fully mobilize their massive reserves. The idea called for a massive concentration against the French, leaving the Eastern border with Russia lightly held. The hope was that in the 6 weeks France would be crushed and the German forces there could then be moved quickly east to face the Russians with Germany's western flank now secure. The only reason the Germans moved against France in 1914, is because they had to knock France out of the war in the opening moves thanks to France being treaty bound to Russia. The whole thing was an attempt to avoid fighting a war on two fronts. Of course when it came to it in 1914 the plan failed because France was not knocked out of the war in 6 weeks and Russia also mobilized and went on the offensive far faster than the Germans thought they would. The result was that instead of a short, sharp war on one then another front, Germany was confronted with a long, drawn out war of attrition on two fronts.