We think it's safe to say that the Bieber Fever epidemic has overrun Europe!

After nearly causing a state of emergency during the Norway stop of NRJ tour, in promotion of his new album Believe, Justin Bieber ended up in Paris, and caused a massive traffic jam when hundreds of fans gathered outside of Universal Music headquarters to listen to him perform his new single, Boyfriend, with a megaphone off the balcony!

Ch-ch-check it out (above)!

Beforehand he wrote on Twitter:

about to head over to 20-22, rue des Fossés Saint-Jacques here in PARIS! who is coming to sing with me and #WithDanKanter

— Justin Bieber (@justinbieber) June 1, 2012

And after:

Loved singing with all of you #WithDanKanter - just like old times. #AlwaysKidrauhl

— Justin Bieber (@justinbieber) June 1, 2012

Ahhh! It looks like it was so much fun!

You should employ the megaphone technique more often, boy! LOLz!

And ch-ch-check out an equally fabulous - albeit much more intimate - acoustic performance from the Biebs of his newest track, Die In Your Arms, during the Parisian leg of his promo tour...AFTER THE JUMP!