The trip is William's first official visit to the city since his mother died there.
Britain's Prince William (R), the Duke of Cambridge, and Kate, the Duchess of Cambridge, arrive at the British Academy Film Awards (BAFTA) at Royal Albert Hall in London, Britain, on February 12, 2017.
William and Kate's visit has been overshadowed by newspaper criticisms the Duke has faced for his weekend away on a "lads only" ski trip to Verbier.
On Friday morning the Duke and Duchess of Cambridge celebrated St. Patrick's Day with the Irish guards in London.
The Duke and Duchess of Cambridge have met survivors of recent French terror attacks during a visit to the military hospital Les Invalides in Paris.
William and Kate are also planning to attend the Six Nations rugby global between France and Wales at the Stade de France on Saturday.
Britain's Catherine the Duchess of Cambridge arrives for a dinner at the British Embassy in Paris. While Prince William didn't budge, it seems he can't escape his ill-timed vacation that he took in place of attending Commonwealth Day celebrations.
After visiting Les Invalides, Will and Kate made the short journey to the Musée d'Orsay overlooking the Seine.
The Duke said: "We think you are very strong and very fearless, you've made unbelievable progress".
In a nod to the famous Parisian fashion house, Kate wore a Chanel striped cotton tweed waisted frock coat with a box pleated skirt.
Vanity Fair is reporting that sources among "royal watchers" say Duchess Kate is "less than pleased" that William was filmed partying in this manner.
His "lads-only" trip meant he missed a service at London's Westminster Abbey attended by other members of the royal family.
William has announced he is stepping down as an air ambulance helicopter pilot to focus more on royal business.