She's worn the designer on countless royal occasions, including after giving birth to Princess Charlotte in 2015, while posing for photographers on the steps of St. Mary's hospital in London.
The royal couple will visit the military museum Les Invalides with senior French politicians, victims of the 2015 terrorist attacks at the Bataclan theatre in Paris as well as the lorry attack in Nice on Bastille Day a year ago.
For a black tie dinner at the British ambassador's residence that evening, Kate made her third outfit change of the day, into an embellished gown by another of her "go to" designers Jenny Packham.
Kate emphasised her waist with a back Chanel double C belt and she also carried a small burgundy quilted leather top-handle Chanel bag.
Kate Middleton looked elegant on March 18, on day two of her royal visit to Paris with Prince William.
Not long after Prince William hit headlines when leaked footage showed him dancing into the early hours of the morning on a ski trip, and so missing the Commonwealth Day service, he and Kate began their two-day trip to Paris.
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But it was while attending a welcome reception at the British Embassy that the duchess wore a black calf-length Alexander McQueen dress that was sleeveless and belted; she paired it with strappy black heels and accessorized with an oversize necklace.
The Duchess opted for a tweed waisted frock coat with a box pleated skirt and bracelet sleeves in blue and red that looked like a customised version of a look from Chanel's 2017 pre-Spring ready-to-wear collection, now on sale for £8,350.
French President Francois Hollande seemed happy to welcome Will and Kate, despite possible lingering bitterness from the coming Brexit divorce proceedings.
In a nod to the famous Parisian fashion house, Kate wore a Chanel striped cotton tweed waisted frock coat with a box pleated skirt.
After that stop, they continued to the Trocadéro, where they met with a group of young people from France and the U.K.at a "Neighbors in Action" event, and also managed to squeeze in a Wales vs. France rugby match.