Police passed out flyers warning merchants about the recent acts of voyeurism.
Employees are asked to do regular checks of bathrooms to see if there is anything suspicious.
The Cosi manager checked the bathroom after seeing a news reports about 51-year-old Paul Deveau, of Hartford, who is charged with voyeurism in the Starbucks incident.
Deveau is due to appear Aug. 11 in Hartford Superior Court.
Police do not know if Deveau was connected to the camera at Cosi, and he has not been charged in connection with it.