The Hollywood actress opted for casual attire for their late-night outing which saw them heading to a restaurant with friends and taking in the sights of the French capital.

Wearing black denim shorts and a plain navy vest top, the Avengers star scraped her hair into a messy bun.

She chose to sex-up her dressed-down look with a pair of black-rimmed spectacles which oozed secretary chic as she puffed away on a cigarette.

New York–based advertising creative director Naylor dressed casually too in jeans and a white shirt which exposed his tattooed arms.

Scarlett Johansson and Ryan Reynolds Scarlett Johansson and Ryan Reynolds were previously married

It certainly appears like they're still in the honeymoon period of their relationship as they strolled with their arms around each other in the city of love.

Scarlett, 27, has been linked to Nate since February this year after they were spotted on a date in New York City.

She previously gushed about him in April's edition of Vogue, saying he's handled the media attention surrounding the pair very well.

She said: '[The media attention] must be very strange for him. I mean, it's got to be an adjustment for him way more than it was for me [when my career started] at 19. But he's really remarkably good about it.'

Scarlett dated Mystic River actor Sean Penn, 51, last year for five months. She was previously married to actor Ryan Reynolds in September 2008 but the pair split in December 2010.