San Francisco Ballet board chairman George James has announced that the company will perform at the annual Festival de Paris in May. So, it comes as no surprise that the season opener this weekend is titled "A Paris." Artistic director Helgi Tomasson said the San Francisco Ballet was the only American company to be invited to the festival, which this year celebrates the bicentennial of the French revolution. He said the program will include four performances of his full-length "Swan Lake." A mixed repertory will also include George Balanchine's "Theme and Variations," David Bintley's, "The Son of Horus," and William Forsythe's "New Sleep."