Jennifer Aniston and boyfriend Justin Theroux are seen on 'Rue Saint Honore' on June 11, 2012 in Paris, France. Credit: Marc Piasecki/FilmMagic

From the moment they touched down in Paris, France, Sunday, Jennifer Aniston and Justin Theroux made no attempts to hide their affection.

"They were hugging and kissing as much as possible," an onlooker at Charles de Gaulle airport tells Us Weekly. "They got airline priority to get through customs and security, but were in no hurry. They were just so happy to be together and starting a visit to Paris as a couple."

Theroux, 40, and Aniston, 43 -- who wore baggy Vivienne Westwood jeans and a fitted Balmain blazer -- were whisked away by limousine and taken to their hotel.

The following morning, Aniston and Theroux were spotted strolling next to the Tuileries Gardens, on the banks of the River Seine next to the Louvre Museum. "It rained at one point, but Justin had an umbrella to keep them dry," according to an eyewitness. Aniston wore the same Balmain blazer, which she paired with tighter, cuffed jeans and white sneakers.

Later that afternoon, Wanderlust costars Aniston and Theroux -- who took their romance public one year ago -- went sightseeing at the Palais Royal gardens.

For Aniston, Theroux is a welcome change compared to exes like Brad Pitt and John Mayer. "He makes her feel safe and secure when she's with him. A lot of her insecurities melt away," an Aniston pal told Us in 2011. "Their relationship is completely different than any of her other ones. Everything about Justin feels right."