Camilla admitted she was "dreading" speaking publicly today, and asked her audience to excuse her "rather rusty French".
She said it had been 50 years since she had spent six months studying French and French Literature at the Institut Britannique in Paris as a teenager in the Sixties.
The Duchess' day started on the platform of St. Pancras station in London, from where she took the Eurostar to Gare Du Nord in Paris.
Next she visited the workshop of the charity Emmaus, which was founded shortly after the Second World War when homelessness and poverty was an issue, particularly in large urban areas.
She was accompanied by three representatives from the charity's UK arm, which also helps use social enterprise to allow formerly homeless people make a life for themselves.
After giving her speech, in technically correct French but with an English accent, she commented that the experience had "taken years off my life".
The Duchess, wearing a beige Anna Valentine jacket and patterned summer dress, spent several minutes studying the watches, which had all been cleaned and repaired by members of the Emmaus community.
"You could pick up a little bargain here," she said before adding: "If I had all the time in the world and nobody wanted me I'd spend a fortune in here."
And with the Duke and Duchess of Cambridge expecting their first child this summer, it was perhaps understandable that she paused by a table full of children's toys.
Volunteer Sagno Vassima, who guided the Duchess through the products, said: "Kate and William are expecting a baby, so maybe Camilla had the child in mind."
The Duchess' final stop was a reception at the British Embassy in Paris where she met the food blogger Rachel Khoo and cheese maker Matt Feroze among others.
She is expected to carry out a full day's engagements tomorrow as the trip - paid for by the Prince of Wales - continues, taking in elements of traditional French and Parisian culture.