verb/de.paʁ.ta.ʒe/
to shift the balance between two parties of, or break the tie between, decide between; to divide, separate; to isolate, separate, determine; to distinguish, differentiate, or decide between; to find a winner, break a (or the) tie
“Le maire, par son vote, a départagé le conseil municipal.” — The mayor, with his vote, broke the tie between the council members.
From dé- + partager.