Pushing everything out of their way as they passed since their general attack on 10 May 1940, the German forces entered Bouillon just one day later and continued their ‘Blitzkrieg’ rushing to the west, that is, to the Meuse, in order to make their strategy of ‘Sichelschnitt’ a success up to Dunkerque.
On 12 May at daybreak, the three Divisions of the 19th Panzerkorps commanded by the general Guderian crossed the Semois at Mouzaive. The first Panzer division had the mission of reaching the Meuse quickly at Floing passing through Saint Menges, the 2nd was to go towards Donchery and the 10th to enter Sedan through the Fond de Givonne, a classic route for German invasions, and to then continue up to Balan and Bazeilles.
A few houses built just before hostilities along the Belgian border north of the Sedan area, were said to be fortified but could only briefly delay the inevitable progress of this mechanical torrent.
Lieutenant Boulanger and his four men of the 10th Antitank Battalion of the 78th Regiment of Artillery were responsible for the defence of the fortified house of Saint Menges and started firing at the first enemy tanks at the outskirts of the forest, sacrificing their lives and resisting heroically to the very end. Their 100 comrades from the fort of the Ferté would do the same a few weeks later, marking the end of the Maginot line to the west.
In the afternoon, the Panzers proceeded to the courtyard of the factory of l’Espérance at Gaulier, while the 10th Panzer division invaded the centre of Sedan emptied of its inhabitants.