These incidents led to somewhat sensational developments between the French, British, and German governments. Immediately after the German troops crossed the line, the French government itself gave orders to its own troops to advance, and Frankfurt was occupied on April 6 and Homburg on the following day. The French government proclaimed the necessity of this move on the ground that Articles 42 to 44 of the Treaty of Versailles had been broken by the Germans. The French advance occasioned extreme bitterness of feeling in Germany, more particularly as some of the occupying troops were black; and the attitude of the crowds in Frankfurt became so hostile, that on one occasion the French troops brought a machine-gun into action, and a number of civilians were killed and wounded. The British government also disapproved of the French action, partly because they regarded the advance as an extreme measure which should only have been adopted in the last resort, and still more so because the French move had been made independently, and without the sanction of the other Allied governments. The British held that the enforcement of the terms of the Treaty of Versailles was an affair for the Allies collectively, and not for any single Allied government.