PRINCE William made his first public appearance with Kate and sipped a pint of Guinness after videos of him "dad dancing" and partying on a ski trip emerged.
He was criticised for the timing of his holiday - which saw him miss a major Commonwealth event.
During the parade Kate presenting shamrocks to officers, and even honoured the mascot - an Irish Hound - to sprig of greenery.
William wore his formal military uniform for the parade, while Kate wore a dark green coat paired with a hat.
They appeared relaxed as they spoke with officers and made their first public appearance since the Prince came under fire for his ski trip.
During the tour of France the couple will meet President Francois Hollande and later be guests of honour at a glittering dinner party in Paris on Friday night.
The black-tie event, hosted by Britain's ambassador to France Edward Llewellyn, will celebrate the friendship and cultural ties between the UK and France and among the guests will be celebrities from the worlds of film and sport.
Acclaimed actor Kristin Scott-Thomas is expected to attend along with French acting stars Jean Reno and Audrey Tautou and former Arsenal footballer Robert Pires.
William and Kate's trip comes a few days after the Duke was last on the continent enjoying a skiing break with friends in Verbier.
He has been criticised after many questioned his judgment at missing a major Commonwealth celebration with the Queen for the social event.
The future King and his three pals were seen partying in the public bar after a boozy lunch in Verbier.
Footage taken in the early hours of Monday also emerged showing Wills "dad dancing" in a Swiss nightclub.
The official royal visit comes in the month that Prime Minister Theresa May is expected to trigger Article 50, beginning Brexit negotiations.
William and Kate's trip will be seen as a bid to build on the UK's bilateral relationship with France and they have already been dubbed "Brexit Ambassadors" by the press.
The Cambridges will begin their official visit with a meeting with President Hollande which is likely to be held at his official residence the Elysee Palace.
On Friday evening before the dinner party Mr Llewellyn will host a reception at the embassy to mark the launch of Les Voisins - a celebration of UK-French links - where the Cambridges will meet young French leaders from a range of fields from the arts to fashion and business.
On Saturday the highlight of the day will see William and Kate attend the Six Nations rugby match between Wales and France at the Stade de France.
This will be William's first event as patron of the Welsh Rugby Union, a role he took over from his grandmother the Queen.
The trip to Paris - where William's mother, Diana, Princess of Wales, was killed in a car crash - comes as the Duke prepares to mark the 20th anniversary of her death in August this year.
He is not expected to visit the scene of the crash in the Pont D'Alma tunnel nor commemorate the forthcoming anniversary while in France.
Before travelling to France the Duke, who is Colonel of the Irish Guards, and the Duchess will visit the 1st Battalion Irish Guards at their base in Hounslow, west London to mark St Patrick's Day.
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