In January, they scoped out several Parisian churches as possible wedding venues.
"A romantic wedding in Paris is ever girl's dream, but there is no reason why Olivier should play ball just yet," the source says.
The Olsens continued to release direct-to-video films up to the early 2000s, along with starring in the 1995 feature film It Takes Two.
"Olivier has already been through a painful divorce and is simply happy to have a beautiful girlfriend whom he loves.
It will be Olsen's first marriage and Sarkozy's second.
Mary-Kate Olsen is engaged to marry her boyfriend of nearly two years, French banker Olivier Sarkozy, sources confirm exclusively to Us Weekly.
PHOTOS: The best celeb engagement rings ever Olsen, 27, and Sarkozy, 44 -- half-brother of former French president Nicolas Sarkozy -- first stepped out together in 2012.
"She's clearly very excited about the chance to get married to a very successful, well-educated man, but life isn't always that simple.
He's already got kids and is very happy with his status in life."Of course, a little looking never hurt anybody.
He was previously wed to Charlotte Bernard, with whom he has two kids, Julien, 14, and Margot, 11.
PHOTOS: The Olsen twins through the years "Mary-Kate has made him a better father.
Mary-Kate Olsen and Olivier Sarkozy tied the knot in November 2015, but it is only recently that the fashion designer has opened up about her relationship.
During an interview with The Edit, Mary-Kate spoke about married life with the 47-year-old half-brother of former French President Nicolas Sarkozy, saying, "We don't need so much time to sit and think and ponder.
"Mary-Kate's family thinks Olivier is the best thing to happen to her," an insider tells Us.