Beatrice - the daughter of Prince Andrew and Sarah Ferguson - wore a floral midi dress from The Vampire's Wife, black ankle-strap heels by Carvela Lulu, a pink hat from Julian Garner and a powder blue coat by The LA Dress.
Her property tycoon fiance wore a waistcoat in a similar blue shade.
According to The Mirror, the Paris wedding marks the first time the former Imperial House of France and the House of Hapsburg have reunited since Napoleon married the Archduchess of Austria almost two centuries ago.
The wedding was held at Les Invalides in Paris (where Napoleon's body was returned from St Helena after his political exile from France).
The groom, Jean-Christophe works as a private equity manager in London and is the sole heir of his great-great-great-grandfather Napoleon Bonaparte.
His bride, Countess Olympia, is the great-granddaughter of Karl I of Austria.
Jean-Christophe allegedly proposed with a 40-carat diamond taken from the crown of Napoleon III's wife Eugenie de Montijo - the last empress of France.
Earlier this year, the enormous ring had been stolen from inside an unlocked Mercedes in Paris, but the thief was later caught and her ring returned.
According to The Mirror, the couple is together for romantic reasons, despite sharing an ancestor.
"It's a story of love rather than a nod to history. When I met Olympia, I plunged into her eyes and not into her family tree," Jean-Christophe said after their engagement in May.
"Afterwards we were able to smile at this historical coincidence."
Princess Beatrice and Edo will be tying the knot next year after announcing their engagement on Thursday the 26th of September.
Edoardo proposed to the Princess of York while they were on holiday together in the up-market Italian coastal town of Positano.
In their joint statement, the couple revealed they were "extremely happy" about the prospect of getting married: "We are extremely happy to be able to share the news of our recent engagement."
"We are both so excited to be embarking on this life adventure together and can't wait to be married. We share so many similar interests and values and we know this will stand us in great stead for the years ahead, full of love and happiness."