Possible Clues:

• Old mercantile area of Venice
• Central area of Venice
• Historic center of Venice
• Canal bridge in an industrial town
• An island in Venice
• Buying and selling there with an invoice at last when you're abroad
• Dublin district, or Shakespeare's 'What news on the . . . . . .?'
• Gondolier's familiar sight as upright character, singer on river
• Tailor working in old mercantile quarter of city
• Retired Irish singer in part of Venice