Liv Tyler isn’t just in Paris this week to check out the couture shows — although she did make a front row appearance at Christian Dior already — she’s in the City of Lights with her younger sister Chelsea to ring in her 31st birthday. At the the Blue Soiree at the Hotel Crillon for Lanvin and Acne (celebrating the companies’ joint collaboration on a denim-wear collection), the Lanvin-clad actress tells PEOPLE that she’s “excited” for her getaway. “It’s my birthday tomorrow and I’m going to spend it with my sister and we’re going to a Givenchy show,” says Tyler. “I’m excited to have a little fun here with my sister.” But at that very moment, she was even more excited to see the man of the hour, whom she greeted with hugs and kisses. “I love Alber Elbaz. He’s such a kind man. I love Lanvin — he made it [the dress] for me,” she gushed of the diminutive designer. Other guests in attendance included Eva Mendes, in a swirling Dior dress, and uber-stylist Rachel Zoe.