Ka kammala wannan magana: A 1817, ya auri Nancy de Bardi kuma tare da ita, yana da 'ya'ya hudu. Mahaifinsa, wanda kwarewar sa ta sa ya tsani aristocrats, ya tashe shi cikin tsananin imani na Jamhuriyar Farko. A duk lokacin juyin juya hali, Daular, da kuma sabuntawa mai zuwa, Poisson ba shi da sha'awar siyasa, maimakon haka ya mai da hankali kan lissafi. An nada shi zuwa matsayin baron a 1825, amma bai fitar da difloma ba kuma bai yi amfani da taken ba. A watan Maris na 1818, an zabe shi a matsayin Fellow na Royal Society, a 1822 a matsayin memba na girmamawa na Jami'ar Kimiyya da Kimiyya ta Amirka, kuma a 1823 a matsayin memba na kasashen waje na Royal Swedish Academy of Sciences. Ƙungiyar
juyin juya halin Yuli na 1830 ya yi barazanar rasa duk darajarsa; amma wannan abin kunya ga gwamnatin Louis-Philippe ya kasance da ƙwarewa ta hanyar François Jean Dominique Arago, wanda, yayin da majalisar ministocin ke shirin "sokewa", ya ba shi gayyatar cin abinci a Palais-Royal, inda sarki ɗan ƙasa ya karbe shi a fili, wanda ya "tuna" da shi. Bayan wannan, ba shakka, ƙasƙantar da shi ba zai yiwu ba, kuma shekaru bakwai bayan haka an sanya shi dan Faransa, ba don dalilai na siyasa ba, amma a matsayin wakilin kimiyyar Faransa.