Princess Kate joined her husband Prince William, King Charles III and Queen Camilla on Tuesday as they kicked off France's state visit to the U.K. The royals gathered at RAF Northolt in Windsor, England, to welcome French President Emmanuel Macron and his wife Brigitte at the start of their three-day state visit.

French President Emmanuel Macron and his wife Brigitte arrived in Windsor for the start of a three-day state visit – the first by a French president since 2008. Prince William and Kate Middleton welcomed the dignitaries when they touched down at RAF Northolt in West London,

President Emmanuel Macron greeted Kate Middleton with a kiss towards her hand as the state visit from France began. But did the gesture break protocol? Inside the royal rules.