Crossing the Rhine
When news that the eastern bank of the Rhine around Freiburg undefended De Gaulle immediately saw it as an opportunity to finally launch his war of mobility and convinced the Emperor to immediately give orders for a grand offensive across the Rhine.
So urgent were the orders given that the offensive began on at 10.00pm on the 29th of June with the 1st Army attacking the fortified defences at Longwy and the 2nd Army attacking the city of Metz in order to pin down German forces while the 1st Light Cavalry Division moved to cross the Rhine via the bridges at Breisach and Neuenburg am Rhein which, in a sign of the increasing breakdown in the morale and effectiveness of the Reichsheer, had yet to be demolished in the face of the French advance.
By the end of the month Freiburg was in French hands and Metz had fallen.
At the same time, however, Flanders-Wallonia was continuing to prove a challenge to the French army, even tying up General Dentz’ heavy tanks in a counter-attack on Namur.
And in Persia the Ukrainian army had reached the borders of the Pan-Arabic Federation, completely cutting off the Portuguese expeditionary force which dug into Tehran to make its last stand.
Nevertheless, the balance of power in the European theatre had decisively changed - not least because the manpower of former north France, faced with a choice between a French Emperor and a German Kaiser, was now being tapped by the French military to provide desperately needed reinforcements. Furthermore, in many cases, former Royal French units, particularly those which had mutinied, joined the French army en masse - with a notable example being the 1st Royal French Fleet, including the aircraft carrier Joffre, under Vice-Admiral Godfroy who all changed allegiance bar a small minority of officers who were treated as prisoners of war.
Following the capture of Freiburg the 1st Light Cavalry began a race north along the eastern bank of the Rhine, moving in a broad front which captured all the towns and villages along the Rhine south of Darmstadt before crossing westwards to seize Mainz and cut off lines of supply to the Germans still fighting in Alsace-Lorraine.
Given the small size of the 1st Light Cavalry compared to the area occupied, their path was rapidly followed by reinforcements freed up by the breaking of the Longwy line.
From here the war of mobility began in earnest with the airfields and city of Frankfurt being captured along with many of the aircraft and crew of the Deutsche Luftstreitskräfte who were cuahgt unawares by the speed of the French advance.
The German military government found it impossible to prevent the spread of news of the French advances into the German heartland and, with the Reichsheer having been both bled dry and surrounded in Alsace-Lorraine, also found the French advance impossible to halt.
And with the spread of the news came the steady collapse of the morale of the German people as vast swathes of Germany continued to fall to the enemy without even token resistance being made while the German military tried desperately to form a line of defence along the Weser river and around the naval base at Wilhelmshaven, where sailors found themselves pressed into duty as soldiers, and effectively abandoning the entirety of Germany west of the Weser to the French and the Austrians.
By the 11th of July the entirety of the Rhineland, Alsace-Lorraine and Luxembourg was in French hands along with Brussels which, despite fierce street-to-street defence by the Flanders-Wallonian army, had all but fallen. The war of mobility was proving a resounding success with the German military on the brink of collapse.