I have Renato’s marriage certificate (with his father’s name Giuseppe Jais listed), death certificate and notification of divorce.

I do also have records of non-naturalisation to the UK, but that doesn’t help with finding his birth place

Hi, I am searching for grandfather’s birth municipality for an acquisition of citizenship Jure Sanguinis.

The information I have is:
Name: Renato Jais
Date of Birth: 29 August 1928
Place of Birth: Italy (exact municipality unknown)
Father’s Name: Giuseppe Jais

I also have his marriage and divorced ...