PTK
11 Dec 2019 #31
My father was born in France in 1916 to both Polish parents.
France didn't change fromjus sanguinis tojus soli until 1927, and then only for those born on French soil of a French mother. Unless your grandparents naturalised some time before your father turned 18, he should still be considered a Polish citizen. The fact that he served in the Polish Army during WWII should avoid any further questions if you can document it.