Johnny Barnes, nominated by Mayor Marion Barry for a seat on the District of Columbia's rent control board, withdrew his name yesterday from consideration for the post.

Barnes, a lawyer and legislative counsel to Del. Walter E. Fauntory (D-D.C.), recently announced his candidacy for the Democratic nomination to the Ward 7 seat on the D.C. City Council now held by Willie J. Hardy.

At a council hearing last Thursday on his nomination to the Rental Accommodations Commission -- the formal name of the rent board -- witnesses representing the city's real estate industry said Barnes' candidacy might conflict with his commission duties.

Although disagreeing with this contention, Barnes notified the council yesterday that he was withdrawing. When he accepted Barry's nomination, Barnes said, he had not yet decided to run for the council.

Hardy has not announced her candidacy for reelection, but said yesterday there is no question she will do so.

Nadine P. Winter (D-Ward 6), chairman pro tem of the council, temporarily withdrew yesterday the name of another Barry nominee to the rent board. The nominee, Despina Kanales, was nominated as a neutral public member of the board, but is currently a tenant of an apartment building being converted to condominum ownership. When the conversion is completed and Kanales ceases being a tenant, Winter said consideration of her nomination will be revived.

The council is scheduled to act today on the confirmation of six other nominees to the commission.