Paolini and fellow Italian Sara Errani fought back from a set down to defeat Marta Kostyuk and Elena-Gabriela Ruse 1-6, 6-4, 6-1.
Paolini had never made it past the second round of a Grand Slam in singles before this year.
This is the first time she has got further than the third round in doubles at a major.
Paolini, who will face red-hot favourite and reigning champion Iga Swiatek in Saturday's singles final, is bidding to become the first woman to complete the singles-doubles double at the French Open since Barbora Krejcikova in 2021.
The Czech was the first since Mary Pierce in 2000.
Paolini and Errani will face either Caroline Dolehide and Desirae Krawczyk or Coco Gauff and Katerina Siniakova in the doubles final.