Berrymans is transferring its allegiance to another firm in Belgium, which will be set up in August by Philippe de Clercq, currently a partner at Baedens.
Paul Taylor, national senior partner at Berrymans, says the move will allow the firm to form a triumvirate between Brussels and its Paris alliance with Bertagna-Gruia Dufaut Berrymans.
He says the firm already has a close relationship with de Clercq because he has handled all Berrymans' work in Brussels for several years.
The new firm will come under Berrymans' alliance, BLM Europe, which was closed to Baedens because it already had a relationship with another Paris-based firm.
Taylor says Bertagna-Gruia Dufaut Berrymans had pushed to establish an alliance with a Brussels firm.
He adds: "I think we would have considered doing this anyway, but it was the French firm that originally organised the meeting to discuss it."
De Clercq, who is quitting Baedens after 10 years, says: "It will be easier for me to set up a firm and fully integrate my ideas. Because of a generational conflict between myself and Baedens this was not possible before."
The new firm will be set up with three lawyers - one of whom is also joining from Baedens - but is expected to have four by the end of the year.