French artist Daniel Buren opened a two-venue exhibition in Chelsea last night that also, via a wheatpasted poster campaign, extends his trademark vertical stripes into the streets of New York. The shows, at Friedrich Petzel's new location on West 18th Street, and at Bortolami Gallery, the artist's New York representative, juxtapose 1970s paper wall works (at Petzel) with new pieces integrating glowing fiber optics (at Bortolami).

The dealers threw a party for Buren at the tongue-twisting new Bocca di Bacco restaurant, on Ninth Avenue, not only to celebrate the exhibitions but also to mark the 51st wedding anniversary of Buren and his wife, Chantal.

"But I'm not supposed to know about that part," Buren, a diminutive, soft-spoken septuagenarian, told A.i.A. at Bortolami during the opening reception. "If Chantal knew, I think she would collapse."

"Yes, it's our anniversary," Chantal later acknowledged, "but I'm sure Daniel wouldn't want you to report on that."

Dominated by giant, colorful balloons in floral designs (obtained, a gallery staffer told me, at the Balloon Saloon), the dining room looked a bit like a Jeff Koons installation gone wrong. "The decor is for their anniversary, of course," Stefania Bortolami told A.i.A. "We got some round shapes to complement the straight lines of Daniel's stripes."

Buren was happy to see some old friends. "Anne Rorimer came from Chicago just for this," he said, with some satisfaction. "And Lawrence [Weiner] is here."

"But," he added, "Lawrence I see all the time." Also in attendance were Allan McCollum, Richard Aldrich and Anna Ostoya, who is also represented by Bortolami.

"His essay ‘Achtung!' was formative for me when I read it in school," Ostoya, a young Polish-born artist who lives in New York, told A.i.A. "Of course I was very opposed to it. Isn't that what you're supposed to do, as a student? Define yourself in opposition to the masters?"

Rorimer, a former curator at the Art Institute of Chicago, fondly remembered commissioning Buren installations there, including Up and Down, In and Out, Step by Step: a Sculpture (1977). "For that piece, he applied stripes to the risers of the grand staircase of the museum's Michigan Avenue entrance," Rorimer said. "It turned the architecture into a sculpture."

"And for Watch the Doors, Please!, he striped the doors of the commuter trains that run under the museum," she said. She even recalled the dates. "That ran—literally!—from October 1980 to May 1982."

A woman in her twenties who was involved with the wheat pasting campaign, who wished to remain anonymous due to the illegality of the enterprise (and who stressed that she's not affiliated with the gallery) was enthusiastic about the experience. "This is the closest I've ever been to being an artist."

Bortolami made some very brief remarks, noting that this was the second time Buren had done a two-venue New York City exhibition. "The first was with Leo Castelli and John Weber Gallery," she said, and, raising her glass to Petzel, said, "I hope I'm Castelli!"

Without missing a beat, Petzel shot back, "I'm not dead yet!" and wished the happy couple 50 more years.