Sollozzo chose Louis Restaurant in the Bronx for the meeting with Michael. This means he had to have discussed the issue with Barzini and/or Tattaglia. I think they were beating a tactical retreat to create a phony peace, so they did not expect the night to turn violent.

"Michael agrees to meet me but he wants it to be a public place...a bar or a restaurant where he'll safe. Louis is chosen, but they try to keep it a secret from the Corleones.

When they do learn the location, Tessio calls it "perfect for us." And he then goes on to describe the bathroom with the box and the chain thing.

My question is in whose territory was this place? IF it was Tatt or Sol, wouldn't that have made the Corleone's nervious? If it was Cuneo or Stracci wouldn't that make them suspects?