Why was France unhappy with Germany prior to World War 1?

France was unhappy with Germany prior to World War I largely due to the lingering resentment from the Franco-Prussian War (1870-1871), in which France was defeated and lost the territories of Alsace and Lorraine. This loss not only humiliated France but also fueled a desire for revenge and the restoration of national pride. Additionally, France viewed Germany's rapid industrial and military expansion as a direct threat to its own security and influence in Europe, leading to a complex web of alliances and tensions that contributed to the outbreak of the war.