Here is France's January 20, 1966 .05 fr "makeup stamp" (Sc #1142) showing the coat of arms of the city of Auch, Gascony in the southwest of the country.
From Google, "The arms represent the two co-lords who exercised their power under the Ancien Regime: the archbishop and the Count of Armagnac. The archiepiscopal power is symbolized by the paschal lamb, while the lion is taken from the coat of arms of the Counts d'Armagnac."
Regarding the paschal lamb, from catholicculture.com, "The lamb eaten at the Passover of the Jews. According to the Mosaic Law, the lambs were first to be sacrificed in the afternoon of the fourteenth of Nisan...Christ as the Messiah was 'sacrificed for us', and thus became for those who believe in Him the Paschal Lamb."