Mezue ahịrịokwu na-esonụ: N'April 1805, a họpụtara Saint-Germain ka ọ bụrụ ọchịagha nke brigade ma nye ya iwu na Etienne de Nansouty's 1st heavy cavalry division ma si otú a na-eme mkpọsa na Grande Armée n'oge Agha nke atọ nke Njikọ na
Agha nke Njikọ nke Anọ n'oge 1805-1806. Onye Baron nke Alaeze Ukwu na Jenụwarị 1809, Saint-Germain duziri otu brigade nke Nansouty's cuirassiers na agha nke Aspern-Essling ma bulie ya n'ọkwa nke ngalaba na July 1809. Na 1812, o sonyere na Mgbasa Ozi na Russia, ebe ọ merụrụ ahụ na agha Borodino. Na Septemba 1813, e mere Saint-Germain ka ọ bụrụ Count nke Alaeze Ukwu ma sonye n'agha nke Hanau, ebe o nwere aka na ịmanye ngafe nke ihe ndị Grande Armée na France. N'oge agha ahụ a lụrụ na France n'afọ 1814, o duziri ọtụtụ ndị agha ịnyịnya a ma ama. N'oge mweghachi nke Bourbon ọ mere nke ọma ma na 1818 a họpụtara ya onye nyocha nke ndị agha na-agba ịnyịnya.