, Celia, who has been married to
Good Morning Britain presenter Piers for ten years, described getting up at 6.15am to prepare to check out of the property.
“I knew the second I walked into the sitting room that something was wrong," she said.
"The previous night had been spent getting our rented house ready for ‘check-out’ – but the place was a mess.
"My handbag was upside-down on the sofa, the box I keep my jewellery in lying empty beside it."
French police later told the couple that the intruder had been in the home only 15 minutes earlier.
Celia said she then had a realisation that made her "feel sick".
"The up-turned handbag found in the sitting room had originally been on a chair in our bedroom," she wrote.
"They must have crept in there and stood inches away from us while we slept."
Police also said that they see upticks in burglaries on the French Riviera over summer as criminals come to the region to "do the season".
Other celebrities to have been targeted in the past while holidaying in the area include Trinny Woodall, Patrick Viera, and Richard Hammond.
"After all the stories I’ve heard over the past few days from neighbours and friends who have been burgled in that same area, I feel grateful that we got off as lightly as we did," Celia wrote.
Pictures from last month showed Morgan and family relaxing in the sun in a huge villa in St Tropez.
He and Celia were reportedly accompanied on the trip by their eight-year-old daughter Elise and Morgan's three sons, Spencer, 27, Stanley, 23, and Bertie, 19.
At the start of the trip, the 55-year-old posted a photo of himself wearing a face mask as he waited to set off from Heathrow Airport.
A caption read: "I’m a washed up, knackered pathetic excuse for a celebrity... get me outta here.
"Bye Britain, it’s been... surreal."
Recent months have seen the presenter become one of the strongest critics of the government and its response to the coronavirus pandemic.
Piers announced at the start of last month that he would not return to Good Morning Britain until September as he spent some time away with his family.
Piers Morgan reunites with Amanda Holden as families get together for boozy lunch in Saint Tropez