Katy Perry loves to talk shit about Lady Gaga online, but has no problem covering her songs on stage.

Katy covered Gaga's "Born This Way" during a show at Le Zenith concert hall in Paris, where she's in town for Fashion Week.

I love Katy's songs, but she needs to just stick to singing her own hits. The Gaga cover was pretty bad. Check it out below and you be the judge...