He is also suing to block commissioners and/or County Auditor Frank Russo from entering into any contracts longer than five months or make any appointments to the problem-plagued Boards of Revision.
That's how much time the old county government has to operate before it's replaced by the new voter-approved reform government.
Lanci is bringing the lawsuit as a Cuyahoga County taxpayer.
"Should the Board of County Commissioners be permitted to close a sale of that asset (the Ameritrust Tower) in the waning five months of existence, Lanci and all similarly situated citizens of Cuyahoga County will be irreparably harmed for which there is no adequate remedy at law," the lawsuit states.
The county has at least $40 million invested in the Ameritust Tower, including purchase price and asbestos removal.
Plans to use it as a county office building or a private mix of housing and business never came to pass.
One county option is to sell it for as little as $22.5 million, a potential loss of $18 million.
Lanci claims he fears some county leaders will push deals to help friends among their final official acts.
Russo's spokesman Destin Ramsey said county government is already avoiding making any long-term deals. He said Russo has no comment.