A Boston-based partner at Burns & Levinson has filed an age discrimination complaint in a state court action against the firm, accusing it of targeting him in a campaign to push him into retirement after he turned 67 years old.

Brian D. Bixby, 71, a partner who co-chaired the firm’s private client group for nearly 25 years, claims he was demoted and stripped of the co-chair position in an effort to “push him to retire,” according to the Suffolk County suit filed Monday by his counsel, Inga S. Bernstein, a partner, and Niamh S. Gibbons, of counsel, with Zalkind Duncan & Bernstein.