A series of intimate snaps, captured by photographer Sophie Margue, were shared before the big day, and the young prince had a day to remember as he tucked into a giant cake that was topped with toy trains. He even showed off his new tricycle.
Recommended videoYou may also likeWATCH: Meet the future Kings and Queens
Francois looks to be the spitting image of Britain's Prince Louis in this sweet photograph. The youngster clearly enjoyed his wooden tricycle as he wheeled himself around the family's expansive garden.
It appears the little tyke is a fan of trains, with his gorgeous cake featuring a fondant train on the top. It was carrying the number two behind it. How sweet!
Francois was joined by his older brother, Prince Charles, and father, Hereditary Duke Guillaume, in their back garden, but there was another family member on full display – their chicken, which Francois looked utterly enchanted by.
In a sweet follow-up snap, the family is joined by mother, Hereditary Duchess Stephanie. Francois was the centre of attention, with Charles even placing his hand on his younger brother.
Francois took fashion inspiration from his father, with the duo both wearing navy jumpers. But while Guillaume wore tan trousers, little Francois had the sweetest pair of dungarees on.
Stephanie absolutely doted on her young son in this sweet photo.
The youngster's birthday comes shortly after his older brother marked a major milestone. Last week, the five-year-old was taken for his first royal engagement, the inauguration of a school named in his honour.
Charles was seen cutting the ribbon at the event and joining his parents for a tour of the facilities, taking great interest in a painting of a train on the wall.
Charles enjoyed a major moment last week
The future heir to the throne was dressed smartly for his first official outing, wearing a maroon jumper and brown trousers. A particularly sweet moment saw the future heir in his father's arms as they unveiled a plaque confirming the school's name.
The youngster was also seen receiving gifts from students at the school and signing his name in the school's registry book.
ROYAL FAN? JOIN THE CLUB
Welcome to The HELLO! Royal Club, where thousands of royal fans like you get to delve deeper into the wonderful world of royalty every day. Want to join them? Just click the button below for a list of club benefits and joining information.
LISTEN: Why Princess Kate's fashion doesn't feature in new palace exhibition
Sign up to HELLO! Daily for all the latest and best royal coverage
By entering your details, you are agreeing to HELLO! Magazine User Data Protection Policy. You can unsubscribe at any time. For more information please click here.
Prince Jacques and Princess Gabriella made a rare public appearance to join their parents, aunts and cousins for the annual celebrations at the Prince's Palace
Grand Duke Henri and Grand Duchess Maria Teresa's only daughter and her husband, Nicolas Bagory, are already parents to 17-month-old daughter, Victoire
The Prince of Wales revealed his youngest children's hobby in a new interview with Schitts Creek's Eugene Levy for his Apple TV+ show The Reluctant Traveler
After the Luxembourg change of throne, take a look back at some of most incredible gowns and outfits wore for royal coronations and inauguration ceremonies
