The `Firework` singer - who split with husband Russell Brand in December after just 14 months of marriage - was spotted "flirting" with Baptiste Giabiconi as they left a Paris hotel, according to reports.
The 22-year-old face of Chanel previously admitted he would "marry" Katy, 27, if he could make her divorce Russell - and it looks as though his affections might be returned.
A source told The Sun newspaper: "They were with a group of people, but they looked very much like a couple in love.
"He was never more than a foot away from her and they were very flirty. There was a lot of whispering, shared jokes and they were really flirting. "They made a very good-looking couple."
In a January 2011 interview with dansk magazine, Baptiste professed his love for Katy. He said: I like what she radiates. She has spirit and she doesn`t come across forced. And I also think she`s hot. If I could make her divorce her husband, I`d marry her."
Meanwhile Russell is believed to have already moved on with artist Oriela Medellin Amieiro, who he is said to have met in yoga class.