on 15 may, 10th panzer and "großdeutschland" led a thrust into the stonne heights to bring them under german control. here, faced with nearly invulnerable char b1 bis heavy tanks on the french sides that were not shaken by german anti-tank weaponry, the german units, especially "großdeutschland", took considerable casualties. famously, the french tank ace pierre billotte drove his char b1 bis into a german ambush intentionally, then destroyed two panzer ivs, eleven panzer iiis and two anti-tank guns and was hit over 140 times, with not a single shot able to penetrate the heavy armor of his tank, nicknamed "eure". in 10th panzer's and "großdeutschland's" back line, additional german forces could safely cross the meuse, with 29th infantry division of 16th army the first to arrive to reinforce 10th panzer division. during the night from the 15th to the 16th, guderian protested against suggestions by panzer group kleist's command staff to stop the advance and to focus on the bridgehead. guderian feared a loss of momentum that would allow the allies to regain their footing and formulate a viable defense. rifle regiment 1 of 1st panzer division faced off against a brigade of french spahi light cavalry, which hermann balck cited as "the best troops [he] faced in both wars". the spahi refused to surrender their entrenched position and almost all of them were killed.