Second in line to the throne William, who is one day expected to be head of the Commonwealth, is on the EAAA rota for more flying stints this week and next.
William and Kate also will meet with survivors and first responders from the July 2016 terror attack in Nice, France, and the November 2015 terror attack at the Bataclan, ABC News said.
This time, the visit coincides with the recent endorsement by Britain's Parliament to trigger Article 50 of the European Constitution, authorizing the country's exit negotiations from the European Union that resulted from last June's stunning referendum in which 52% of voters backed the departure.
While they are there on the request of the Foreign Office, a Royal spokesman emphasised the trip was intended in the spirit of celebrating friendship across the Channel.
Kate Middleton and Prince William attended the annual Irish Guards St Patrick's Day Parade at Household Cavalry Barracks today (March 17, 2017) in London, England.
William, 34, reassured the French in his speech at the British Embassy that the partnership remains between Great Britain and France.
The couple is reportedly staying at the British ambassador's residence during their visit.
"Like all neighbors, sometimes our two nations encourage each other through mutual support".
Among the guests were the actor Jean Reno, actress Kristin Scott Thomas and former Arsenal footballer Robert Pires. They also plan to attend a France-Wales rugby match.
Although no official commemoration is planned during the trip, it will be impossible to escape the poignancy of Diana's eldest son visiting the city where she died on August 31, 1997.
Earlier this week, Prince William hit the headlines after he chose to miss the Commonwealth Day service in favour of a ski trip with friends Guy Pelly, James Meade and Tom van Straubenzee. The most popular royal couple on the planet comes for a 48-hour official visit to our lovely capital.
It only shows that Prince Charles is spending more time bonding with Prince Harry rather that Prince William.
We'll see what the queen has to say about all this.
This is in comparison to The Queen's 24 days that she has worked so far this year.
During a holiday in the south of France in 2012, long lens photographs were taken showing Kate topless.