You can check for Paris jazz venues at this site
http://www.parisjazzclub.net/
As for Paris Jazz Corner, their rue de Nancy shop is open to the public on Tuesdays and Thursdays (from 11 to 19)
but their main shop is in the Latin Quarter at 5/7 Rue de Navarre (phone 0143367892). That one is open daily from Tuesdays to Saturday from 12 to 20). It's opposite the picturesque Arenes de Lutece square.