 Nyorai mberi kweiyi ndima - Akazvarwa mumhuri yevakuru veAncien Régime, Desvaux akagamuchirwa paChikoro cheArtillery cheChâlons muna 1792, asati ajoina Hondo yeAlps, iyo yaaizotora chikamu mukukombwa kweLyon. Akabva ashanda pasi pehutungamiri hwaGeneral Jacques François Dugommier muHondo yeOriental-Pyrenees, asati atumidzwa aide-de-camp kuna general Saint-Rémy muna Ndira 1796 uye akatumirwa kuItari. Aizotora chikamu mukubatana kwemauto akati wandei pakati pa17981799, anonyanya kuzivikanwa paNovi neMincio. Anova aide-de-camp kuna mukuru Auguste de Marmont uye anokwidziridzwa pachinzvimbo checolonel muna 1803, achitora chikamu mukukombwa kweUlm, kwaakakuvadzwa, asati abatwa nemuvengi muhondo yeJudenburg. Asunungurwa pashure peChibvumirano chePressburg pakupera kwa 1805, akapedza gore rakatevera achishumira somutungamiriri wezvombo zveFrance muDalmatia uye ipapo Friuli. Muna 1809, akatora chikamu muHondo yeChishanu Chibvumirano uye akasimudzirwa kuva brigadier general; mushure mekupera kwehondo muAustria, akapiwa kutungamira kweanokudzwa mabhiza epfuti yeImperial Guard. A Baron weHumambo kubva muna 1810, Desvaux akabata basa rake muVachengeti uye aive chikamu cheGrande Armée panguva yeRussia Campaign uyezve Hondo yeChitanhatu Mubatanidzwa. Akakwidziridzwa kuva mukuru weboka munaNovember 1813 uye muna 1814, panguva yeFrance Campaign, akapiwa mutungamiri wezvombo zveuto reLyon, pasi paMarshal Pierre Augereau. Mukati meZuva Rezana, Desvaux akabatana naNapoleon uye akapiwa kutonga kwechikwata chose chevarwi. Akaurayiwa muhondo paHondo yeWaterloo. Zita rake rakanyorwa pasi peArc de Triomphe, Shongwe yokuchamhembe. 