The sector includes the following major fortified positions. The casemates were generally about apart, with gaps in areas of marshy ground or old sections of the Rhine.   172nd Fortress Infantry Regiment ("172e Régiment d'Infanterie de Forteresse (RIF)"), Lt. Colonel Le Mouel, command post at Fort Pétain, then Schiltigheim. "First line (riverbank)"  "First line (riverbank)"  "Third line (villages)"  34th Fortress Infantry Regiment ("34e Régiment d'Infanterie de Forteresse (RIF)"), Lt. Colonel Brocart. "First line (riverbank)"  "Second line (shelters)"  "Third line (villages)"  "First line (riverbank)"  "Third line (villages)"  Peacetime barracks and support:   The French Rhine defences did not see significant action until the middle of June 1940. By this time the main French army was in full retreat. The casemate lines along the Rhine were not supported by significant mobile forces or field artillery, which had been diverted to more urgent tasks. The casemates were designed to be mutually supporting, with fields of fire along the Rhine rather than across it. The first line was exposed to enemy fire from across the Rhine, a distance of a few hundred metres. German forces, under General Dollmann, amounted to seven divisions of the Seventh Army, supported by about three hundred artillery pieces, chiefly concentrated opposite the SF Colmar, just to the south. The codename "Kleiner Bär" ("Little Bear"or "Lesser Bear") was given to the planned German cross-Rhine operation. The initial attack started at 0900 (some sources say 1000) on 15 June with artillery bombardments. 8.8 cm guns concentrated on the French positions just across the river, destroying many in a few minutes. At 0920 the first assault crossed the river, composed of the German 218th Infantry Division at Schoenau, the 221st Infantry Division at Limbourg and the 239th Infantry Division at Sponeck, all in the SF Colmar. Supporting operations were carried out by the 554th ID at Neuf-Brisach (SF Colmar) and the 557th ID at Rhinau in the Lower Rhine sector. The 557th ID's attack at Rhinau was intended to be a diversionary attack, but it produced significant success.