50 C. postal stamp with overprint "fortress Lorient", by a value variety "inverted overprint", horizontal strip of four from left margin of sheet (left stamp with variety) as correctly franked multiple franking on cover from the "fortress Lorient 10. April 1945" to La Baule with reverse arrival stamp "La Baule 20. 4. 45", without any signs, photo expertize Lothar autumn VP (2015) : "partly small weak typical age traces on cover and stamps, the be tolerated must for a war document from the time 1945. the other condition is perfect and above average good for this visually very representative cover. The stamps have only a very small printing of 1. 800 pieces. A strip of four and even with overprint t_te-b_che pair is very rare. Covers of the fortress post Lorient are general very rare. Correctly franked multiple franking are especially rare. "