A member of Rockville's Historic District Commission has been accused of violating the city ethics law when he sued the city on behalf of a client over a zoning decision. Charles S. Rand, a Rockville lawyer, filed suit in Montgomery Circuit Court in April for Sheraton Potomac Inn, challenging a March ruling by the city board of appeals permitting a Sheraton competitor, the Marriott Corp., to build a Courtyard Motel at Shady Grove Road and Research Boulevard.

Sheraton is contending that the rezoning, special exception and accompanying variances the board granted are so exorbitant that they amount to "illegal, special-interest spot zoning."

Rockville City Attorney Paul T. Glasgow wrote Rand last month that his dual role as an appointed city official and as lawyer for the Sheraton Potomac Inn was a violation of the ethics law.

A provision in the recently revised law bars elected and appointed officials from representing private parties in litigation against the city. Family members and personal-injury suits are exempt, the provision states.

"In order to achieve compliance with the ordinance, you should take appropriate action to discontinue your representation in connection with these proceedings," Glasgow wrote.

But Rand said he is refusing to drop out of the case. He said the ethics law violates his constitutional right to free speech.

"I am forbidden from challenging Rockville laws in clear contravention of my constitutional rights to speak freely and petition the government for myself and on behalf of others," Rand said.

A violation of the ethics law is considered a misdemeanor, and is punishable by either a $1,000 fine or six months in jail.

Mayor Viola D. Hovsepian and the City Council met last week in closed session to discuss the issue and may come to a decision by the end of the month. Any action to dismiss Rand would have to be taken by the council, Glasgow said.

Appointed to the commission in 1980, Rand is serving his second three-year term on the panel. The commission, whose members are unpaid, reviews proposed changes to properties and buildings within the Rockville Historic District.