thumb|Vichy police escorting French Jewish citizens for deportation during the Marseille roundup, January 1943. Germany's invasion of Poland in 1939 finally caused France and Britain to declare war against Germany. But the Allies did not launch massive assaults and instead kept a defensive stance: this was called the Phoney War in Britain or Drôle de guerre — the funny sort of war — in France. It did not prevent the German army from conquering Poland in a matter of weeks with its innovative Blitzkrieg tactics, also helped by the Soviet Union's attack on Poland.
thumb|Vichy police escorting French Jewish citizens for deportation during the Marseille roundup, January 1943. Germany's invasion of Poland in 1939 finally caused France and Britain to declare war against Germany. But the Allies did not launch massive assaults and instead kept a defensive stance: this was called the Phoney War in Britain or Drôle de guerre — the fu.nny sort of war — in France It did not prevent the German army from conquering Poland in a matter of weeks with its innovative Blitzkrieg tactics, also helped by the Soviet Union's attack on Poland.