Jessica Biel Paris France Airport

Jessica Biel was sans makeup as she arrived in Paris for Fashion Week!

The flight is 12 hours -- can you blame her??

But Jess still looked gorgeous on Saturday. She headed to Paris just after spending time in Las Vegas with on-again beau Justin Timberlake for his golf tournament benefiting the Shriners Hospital for Children.

Biel, 29, and Timberlake, 30, are definitely back together -- though our sources tell us she is trying to take things slowly; Timberlake will have to work to get Jess' trust back after cheating on her.