Kammala jumla mai zuwa: An haife shi a Châteaubriant, Loire-Inférieure (yanzu Loire-Atlantique), Faransa, Chaplais ya yi karatu a Collège Saint-Sauveur a Redon da Jami'ar Rennes, inda ya yi karatun Shari'a da Classics, da nufin zama lauya na ilimi. An dakatar da karatunsa ta yakin duniya na biyu, lokacin da ya yi aiki tare da sojojin Faransa har zuwa lokacin da aka kashe shi.
Hukuncin Armistice na 1940. Wani memba na Resistance na Faransa, Gestapo sun kama Chaplais kuma aka aika zuwa Buchenwald. Don ayyukansa na lokacin yaƙi ya karɓi "Médaille de la Résistance".