The aspect of the boulevards last night was the completest possible contrast to what was seen on Sunday night. The city was under martial law, and the police showed very plainly that they did not intend to be trifled with. Instead of shouting crowds and stone-throwing by excited youths and women, one saw only a few citizens walking slowly along. One group of policemen took shelter from the intermittent showers under the marquise of the Vaudeville Theater, and other detachments were in readiness at corners all along the line of the boulevards, which were dotted with isolated policemen. No one was allowed to loiter. To wait five minutes outside a house was to court investigation and possibly arrest. There was no sound except that of footfalls and a low murmur of conversation. It was the first night of war's stern government. Germany officially declared war upon France at five forty-five this evening. The notification was made by Baron von Schoen, the German Ambassador to France, when he called at the Ministry of Foreign Affairs to ask for his passports. Baron von Schoen declared that his Government had instructed him to inform the Government of the Republic that French aviators had flown over Belgium and that other French aviators had flown over Germany and dropped bombs as far as Nuremberg. He added that this constituted an act of aggression and violation of German territory. M. Viviani listened in silence to Baron von Schoen's statement, and when the German Ambassador had finished, replied that it was absolutely false that French aviators had flown over Belgium and Germany and had dropped bombs. Immediately after this interview, M. Viviani telegraphed to M. Jules Cambon, French Ambassador in Berlin, instructing him to immediately ask for his passports and to make a report on France's protest against the violation of the neutrality of Luxemburg and the ultimatum sent to Belgium. M. Cambon will leave Berlin to-morrow. Since acts of war were committed by German troops two days ago, the delay in the recall of the German Ambassador had appeared inexplicable to the great majority of French people, to whom Baron von Schoen appeared to be decidedly outstopping his welcome. The Ambassador himself seemed conscious of this feeling, for not only did he take care to proceed to the Quai d'Orsay in as inconspicuous a manner as possible, but he also applied to the authorities to detail a policeman to accompany him in his automobile. Baron von Schoen's departure from Paris was a solemn affair. He left the Embassy last, after a vast collection of luggage had gone off in motor-wagons and other vehicles. A few minutes before ten o'clock, wearing a soft felt hat and black frock coat adorned with the rosette of the Legion of Honor and carrying a rainproof coat over his arm, he left in a powerful automobile, which, by way of the Invalides, the Trocadero, and the Boulevard Flandrin, conveyed him to the station.