90 C. Special stamp \"world exhibition\" with 10 C. Postal stamp \"Merkur head\" with turning into, horizontal overprint in type I, properly franked on slightly splotchy superb cover from Dunkerque 12-7-40 to Ghyvelde with arrival postmark on the back from 13.7.40. Photo expertize Krischke and expertise Lothar Herbst VP (2022) : \"the condition of the stamps is perfect, the letter with minimal typically traces of use. \"