Corrected the link...and got the info, that the stamp says "Kriegsmarinearsenal Toulon". Checked this already, there was such an arsenal. And the map is dated 1941. I will order some more detailled screens from it. I wanna see the pencil drawing on the back!
Got an update:
Dont know, what to think of it. Anyone seen such a drawing, like the one on the back? Would be very grateful for any news on that!
Tweaked the image in Photoshop, by increasing the contrast and selecting colors. Awesome! Its a real drawing..or the rest of it. The legend(?) reads from upper left to bottom right "Flugzeug" (airplane), "Tauchfahrt" (dived), "Pei...?", "?", "...koppelte Gegner...?" (enemy ...), "Fühlung?" (contact).