France 1863 20c blue Napoleon Block of 4 Cover Pont L’Eveque to Paris

Cover franked with 20c blue block of four, tied by 2950 "Gros Chiffres" and postmarked with corresponding "Pont L'Eveque" c.d.s. (29 Sept), to Paris, with c.d.s. arrival backstamp and partial TPO transit, pencil signed alongside block, a scarce franking. (Yvert 22)