Polish striker Pajor opened the scoring on 55 minutes and netted again in the 69th minute, with Paralluelo's superb late strike ending the contest before she completed the rout of a stunned Lyon in stoppage time.
Barca's four titles have all been won in the last six seasons, and their overall tally is bettered only by Lyon, who are the record eight-time European champions.
The French club's last title came in 2022.
