This was Andrea and Tatiana's second wedding as they had already held a civil wedding service in Monaco in August.
The beautiful 30-year-old bride wore a bespoke Valentino gown and an elegant cream fur cape. Her long dark hair was swept into an chignon and held in place with a glittering tiara.
Monaco's royal Andrea, 29, who arrived at the church by car, sported a smart grey suit.
The 11th century church had been transformed into a winter wonderland, adorned with boughs and urns of flowers, some of which came from Paris. Candles added to the magical atmosphere.
Andrea and Tatiana, who are a notoriously private couple, had made every effort to keep the wedding an intimate affair and Monegasque police stood guard outside.
Guests, who included, Andrea's mother Princess Caroline, Prince Albert, Charlotte Casiraghi, Princess Alexandra, Pierre Casiraghi and his girlfriend Beatrice Borromeo, all arrived in cars with blacked-out windows. The wedding party were also shielded by dark umbrellas.
Representing Tatiana's side of the family were her mother Vera Rechulski and younger brother Julio Mario Santo Domingo as well as numerous relations. Her brother was thought to be giving her away as Tatiana's father Julio Mario Santo Domingo passed away in 2009.
The man behind Tatiana's spectacular gown, Valentino, also joined the congregation, as did society guests Margherita Missoni, Olympia Scarry and Elisabeth von Thurn und Taxis.
After being pronounced man and wife, the beaming couple exited the church amidst the falling snow and headed for their wedding reception at the Palace hotel.
The royal family have yet to make any pictures of the wedding available.