I've received the email below about the subject. IMDb lists only:
Washington Square Park, Greenwich Village, Manhattan, New York City - no other details
Dear Bryan,
I run a website dedicated to New York film locations and I’m about to add Please Don’t Eat the Daisies. Unfortunately, I’m at a loss for actual locations as most of the film has been shot on a stage. However, I suspect that the restaurant scene was shot at a real New York location, with plenty of cartoon-framed pictures on the wall, I was wondering if you knew of any actual locations used.
I look forward to hearing from you.
Regards,
Mark
W: http://www.onthesetofnewyork.com