evansb ha raggione ! Es ist sicher ein Grunau Baby IIb
Probably the most popular glider built before WWII (thousands) and after, in many countries.
Not exactly a high performance sailplane (max L/D=17), but a nice little one
Some more info
Incidentally, one has logged close to 3 hours on the french version (Nord 1300) in the early eighties
evansb has control