On June 4, 1918, French troops, with the aid of American troops, stopped the Germans at Chateau-Thierry as they attempted to cross the Marne. From the article:
"Part of the 1918 German Spring Offensives, the Battle of Belleau Wood took place between June 1-26 during World War I (1914 to 1918). Fought predominantly by US Marines, victory was achieved after twenty-six days of combat. The main German attack was repulsed on June 4 and US forces began offensive operations on June 6. The battle halted the German Aisne offensive and launched a counterattack in the area. Fighting in the forest was particularly fierce, with the Marines attacking the wood six times before it was finally secured."