While these dramatic events occurred in the north, the French south of the German penetration were attempting to build a new line generally along the Somme and Aisne rivers. Known as the Weygand Line, the new positions emphasized defense in depth in the hope of sealing off German penetrations and permitting prompt local counterattacks. With his forces reduced by half, General Weygand concentrated his greatest strength in the coastal sector, where he expected the Germans to strike for the ports to deny aid from Britain, and on the plain of Champagne east of Reims, which offered ideal ground for tanks. He had correctly divined the German intentions, but the entire Somme portion of the new line was weak from the outset because of German bridgeheads established during the dash to the sea. On June 5 and June 6, Bock’s Army Group B launched what was considered the secondary effort northwest of Paris. Although the French fought with bitter determination, fresh German units soon made the difference. By nightfall on June 8, Bock had achieved a decisive breakthrough. As the French northwest of Paris fell back, they compromised the left flank of the armies on the Aisne. Here, where Rundstedt’s Army Group A launched the German main effort on June 9, gains for the first three days were meager, and even small gains came under immediate French counterattack. Then, on June 11, the French were forced to fall back behind the Marne in deference to their open flank. The next day, as four armored divisions under Guderian broke through, the fate of France was sealed.
Meanwhile, Benito Mussolini’s Fascist Italy declared war on France and Great Britain on June 10. As the French government declared Paris an open city and withdrew, first to Tours and then to Bordeaux, the Germans entered the capital on June 14. On the same day, Army Group C, commanded by Gen. (later Field Marshal) Wilhelm von Leeb, began to attack the Maginot Line and achieved two quick penetrations against a garrison minus its mobile reserves. On June 17, Guderian’s tanks reached the Swiss border, cutting off the 500,000 French still in the big forts.
As Premier Paul Reynaud considered the possibility of withdrawing the government to North Africa to continue the war, Prime Minister Winston Churchill encouraged him on June 16 with an offer of “indissoluble union” with Britain, but a majority of the cabinet voted to request armistice terms. On June 17, the aging World War I hero, Marshal Philippe Petain, heading a new government, asked for an armistice. In the early minutes of June 25, the six-week ordeal ended. France lay prostrate, beaten in a 42-day campaign that stunned the world.
German casualties in the campaign were comparatively light, approximating 156,000, including 27,000 killed and 18,000 missing. The British incurred 68,000 casualties, plus the loss of almost all their weapons and equipment. The French have estimated that they lost 123,600 men killed, missing, and captured and 200,000 wounded. The Germans claimed 1,500,000 prisoners, a not unlikely figure in view of wholesale French surrenders between Petain’s request for an armistice and the final cease-fire.