Kim Kardashian and Katy Perry aren’t just having a Parisian girls’ trip … they’re in town to celebrate Lauren Sanchez‘s impending nuptials — and, they’re looking great while doing it.

The two stars stepped out in the City of Lights Friday to celebrate Sanchez … with Kim pulling up in a strapless black dress that accentuated her cleavage.

While the dress had a train in the back, it did little to hide her legs in the front … though her stockings added an extra layer of mystery to the outfit.

Perry wore a tiny top, skintight mesh leggings … channeling another big pop star in Madonna while she stopped to sign some autographs for fans.

Kris Jenner and Eva Longoria also made it to the event … Kris in classic black and Eva’s wearing a vibrant blue dress.

While everyone else seemed to wear black or other dark colors, Sanchez left no doubt about who was getting married — throwing on a skimpy white dress and flashing a huge grin while she and her pals headed to a party boat on the Seine.

This isn’t the first day of festivities … ’cause Lauren was out with Kim and Katy Thursday too — leaving a dinner joint together.

Lauren’s expected in Cannes soon enough for the annual film festival in the city — though her look-alike already made an appearance — where she’ll accept an award for her philanthropic work.