The San Francisco Mime Troupe has a lot to say about urban real estate development. And it said so at the Theater for the New City last Saturday with wit and high spirits.

Yes, said. Productions by the troupe, which is now 40 years old, have long blended movement with speech and song. In fact, ''City for Sale'' could be called a boisterous little musical comedy with a message. It is set in Coast City, a fictional metropolis that resembles San Francisco. But the problems there are akin to those faced by many great cities, including New York.

The script by Joan Holden and Kate Chumley deals with how unscrupulous real estate developers find ways to evict tenants, especially artists and poor people, from buildings in once-neglected but now increasingly desirable neighborhoods. Directed by Keiko Shimosato and choreographed by Victor Toman, the production gallops along to a jaunty score by Bruce Barthol and Jason Sherbundy that is influenced by jazz and rock. A combo plays with gusto, and the cast belts out the lyrics.

The authors' sympathies are unambiguously with the evicted tenants. Yet the production has interesting dramatic nuances. For instance, the evicted artists occasionally seem boorish slobs. The auto-body shop on the street floor of their building may be polluting the neighborhood with toxic fumes. And the only really likable character is a gullible and essentially good-hearted woman (played with wide-eyed wonder by Stephanie Taylor) who has worked long and hard to buy herself a loft.

Possibly to indicate that everyone may be equally capable of virtue and vice, several performers are cast in wildly contrasting roles. Thus Velina Brown portrays both an aspiring singer and an always ambitious, sporadically well-meaning and all too often corruptible mayor. And Amos Glick is a scruffy artist, a seedy poet and a suave real-estate developer who looks like Dracula.

The production's energy diminishes toward the conclusion. But ''City for Sale'' is never dull. It makes one laugh. It makes one think as well.

It continues through tomorrow at the Theater for the New City, 155 First Avenue, at 10th Street, in the East Village, a neighborhood in which some of the issues raised by the show are especially topical.