Britain's ambassador to France said he hoped the visit to Paris will be a "special day", which will "underline the very close ties" between the two nations.
Lord Llewellyn said the Duke and Duchess' trip would emphasise the neighbourliness between Britain and France, in industries from culture and sport to the arts.
The royal couple embarked on their first official public tour together in France, following several visits for military commemorations and private holidays over the years.
Speaking ahead of the trip, ambassador Mr Llewellyn said: "This is a very exciting and special day, the first official visit by the royal couple, by the Duke and Duchess of Cambridge, to Paris."
He said that, during his four-month time he had been struck by the "deep affection" the French have for the Royal Family.