What is Lupin III's nationality? Apparently, in Lupin III: Green Vs. Red, Zenigata is seen with a file that states Lupin's place of birth as unknown. However, according to this page, this particular work is not considered canon.  

Lupin often refers to himself as French, Zenigata often says he's Japanese and on one occasion Lupin himself stated he's half-French, half-Japanese.
We know both his grandfather and father were French, but we know nothing about his mother (at least I think not).

Is there any source that states where he was born, what his mother's nationality is, or anything else that might suggest his nationality?
Most of the sources stated that Lupin III is half-French, half-Japanese - sources: 1, 2, 3, 4. There are also sources that state that his nationality is unknown - sources: 1, 2. But according to this:


  Lupin is half-French, half-Japanese, though Monkey Punch, Lupin's creator himself said (in materials to promote the first Lupin movie) that he considered Lupin to be of no nationality – a citizen of the world.