Gene Simmons' legal team has taken an ingenious first step in shutting down a website featuring a video that shows Gene in a sex act with a woman who is not his longtime girlfriend, Shannon Tweed.

We're told Gene's lawyers contacted Webmastercentral.com, which is responsible for the content on the website promoting the video -- ordering them to cease and desist because of copyright infringement. How, you ask, is this copyright infringement? Gene's lawyers claim the site had no right to use face paint to promote the skin flick, because face paint is a KISS thing.

And now we're being told, the tape is old and the copyright owner is ... drum roll ... Gene Simmons! Apparently, Gene got wind of the tape a few years back and bought the rights. Who's the apprentice now?

BTW, the tape was shot without Simmons' permission or knowledge -- and may well be illegal. That's why TMZ hasn't run it.