They defeated them at sea for sure. Admiral Graves made two very bad decisions that allowed Admiral de Grasse to defeat him at the Battle of the Chesapeake. Instead of attacking the anchored French ships immediately, Graves chose to wait, and then, when the French fleet started sailing, Graves went right in after them instead of aligning his ships at the mouth of the Chesapeake to rake the advancing French ships. In an equal contest, the French navy at that time was simply superior in gunnery, aggression, and training to the British navy, and de Grassed defeated Graves rather handily and in a well deserved victory.
Also, France won 5 of the 7 Wars of the Coalition during the Revolution and Napoleon's time. They won the First, Second, Third, Fourth, and Fifth Wars of the Coalitions and came to dominate Europe for a period of almost 20 years. They lost the next two due to overwhelming numbers and a decline in their quality. But for that period, they were the most powerful army in Europe, and even after their loss they continued to be the most powerful army in Europe until their defeat in the Franco-Prussian War.
They lost early on in WWII due to faulty Allied strategy. The British and French both agreed to advance to the Dyle River due to the Germans having employed a strategy in the previous world war of outflanking France by invading Belgium. They assumed this would be Germany's strategy as well this time around. They weren't defeated in head on combat, they were defeated because Germany invaded the Netherlands and through the Ardennes, outflanking the Allies on the left and right and cutting them off from France. The bulk of the Allied army was able to withdraw to Dunkirk however because the Germans advanced too fast, outran their supply ran, and were unable to decisively smash the withdrawing BEF. The Germans simply won through superior strategy, because they were outnumbered in everything but planes when they were facing the Allies at the start of the Invasion of France. The French had more tanks and soldiers, and the Germans knew they wouldn't be able to win in a head on contest, so chose their outflanking strategy and it worked very well. It's the same exact strategy that General Tommy Franks employed when he invaded Iraq. He bypassed all the Iraqi strongpoints and headed right for Baghdad, leaving the bulk of the Iraqi military to wither on the vine.
So in conclusion, and based on the stats Malte provided, I would say that France has no more lost or won any greater number of wars than any other major European nation out there, and they certainly had their day in the sun as the world's most powerful land army around the turn of the 19th Century.
