This question is rather vague, but I would assume the piece of land you are referring to is the Rhineland.
The French lost the Rhineland to the Germans at the beginning of World War One (1914-1918). It was a rather important piece of land to the French, as it contained a lot of useful farmland as well as raw material deposits useful for industrial progression. The Germans eventually lost the war in 1918, unexpectedly surrendering (there is controversy as to whether, had they not surrended, they would have actually won World War One). The following year, a treaty was made in which was outlined various sanctions on Germany, such as having to pay costs for damage (reparations), and forbidding Germany to have an army bigger than 100,000 troops. One of these conditions was that the Rhineland was to be given back to the French, and that it would become a demilitarised zone. So the German Army was forced to stay out of the Rhineland.
Hitler became Chancellor of Germany on 30th January 1933, and began to break many conditions of the Treaty of Versailles. The other countries didn't see him as a threat at first, and by the time they did he had become very strong and they didn't want to anger him (Poland was the last straw in Sept 1939). He made the army bigger than 100,000 troops and started manufacturing weapons. He marched in and took back the Rhineland in 1936, where it remained under German control until the latter half of the Second World War.
I don't know whether it is the Rhineland you are talking about, so there's a bit of background so you can work out whether we're on the same wave-length.
Hope that helps.
Qu.mstr
Rhinelands
Yes, they lost a part of France, a bit to Denmark, and Austria.
To help France and Russia defeat Germany. Britain wanted Germany to lose WWI, so they joined France and Russia. Britain was worried that if Germany won WWI, they would be too powerful for England to defeat by themselves, so they joined France and Russia and declared war on Germany.
The French joined in WW1 along with the British side. They had been suffered a lot from the Germans. A lot of damaged properties, big loss of soldiers etc. The government was very pissed off with the germans. Later on by 1919, the treaty of Versaille, when the Germans lost the War, France was invited to the conference as we had known as "the big three" (britain and USA too). This was a great oppurtunity for the French to revenge. They got the Germans to accept the "war guilt" and Germany lost their land to mostly France, Germany also had to pay a lot for reparations. Basically France wanted to weaken the German army.
No, the League of Nations took control of Germany's oversea colonies
Did france loose the Vietnam war?
France did not lose any land to Germany in World War 1, but Germany had handed over land (Alsace-Lorraine) to France after the treaty in June 1919 which they were not happy about as they had alwaus been enemies of the french. well that's just world war 1
Yes, they lost a part of France, a bit to Denmark, and Austria.
Austria lost land to Germany and Italy in 1870.
Germany lost Italy itself.
They lose power and land in North America
Alsace and lorraine
1870
Until 1871, there was no "Germany." The area that became Germany was a lose colection of several several hundred kingdoms, principalities, duchies, bishoprics, fiefdoms and independent cities and towns.
1870
Alsace-Lorraine
25 June 1940
After its defeat in WW1 great Britain and France divided Germany's African territory