Talk about a deluge.

In an instant - the time it took Donovan Preddy, 30, and his micro-goateed pal to gulp down their old-fashioneds at the back of the zinc bar at Parc - the scene at Philadelphia's newest and most buzzed-about restaurant was transformed from a cafe on the square to a cafe on the banks of the Seine.

With five inches of water coursing southward down 18th Street - drenched greeters huddled beneath the front awning, sidewalk diners fleeing inside, guarding their half-finished plates of duck confit - it was, perhaps, time to reflect.

Where did this come from?

No, not the freakish hailstorm Wednesday night, but this newest Stephen Starr concoction that has opened on Rittenhouse Square just as the square is drawing attention for its homeless population.

Parc opened a mere 11 days ago, and immediately started attracting a noisy weeknight crowd of true-believing Starry-eyed loyalists, Rittenhouse blue bloods, after-work paralegals and their jaunty lawyer team leaders, out-of-town bended elbowers, designer-sunglasses-on-blond-haired women being ogled by older men from the safety of the massive dining area, rumpled-suited young businessmen complaining of their girlfriends not committing, international students at a sidewalk table chatting in Arabic with their waiter, a standard poodle nearby lapping at a restaurant-supplied water bowl, and tank-topped and jeans-skirted girlfriends marveling at the rapid pulse of a Wednesday night on Rittenhouse Square.

Rapid pulse of a Wednesday night on Rittenhouse Square?

C'est vrai.

Taking a cue from a Paris bistro (or, maybe more precisely, from Balthazar, the authentic, mega-size copy of a Paris bistro in New York's Soho), Parc has become, in a Philadelphia minute, the place.

At least that's what the 250-odd people jammed into the tile-floored, distressed mirrors-and-art-deco-poster decored, 93-on-the-decibel meter, $9 million restaurant seemed to believe.

And surrounded by all those people and all that noise and all that food, Bordeaux by the bottle, Hoegaarden on tap, $8 martinis, cute barmen from Dublin and Miami, all that joie de Rittenhouse, why not nurse that perception? Where else in Philly were that many people jammed in on a Wednesday night, except maybe the hipster music room Johnny Brenda's in Fishtown, albeit another demographic?

"It's, like, the buzz of the city on weeknights," said Dara Imperatore, 26, as she sat with friend Traci Marabella, 28, at a table near the floor-to-ceiling windows the square. (Yes, that homeless man on the bench can see you, too.)

"A lot of places in Philly are small and crowded and cramped, all the BYOs. This is big and open," Imperatore said.

From this early point, the formula for instant sensation seems to include: Stephen Starr, whose new restaurants draw diehards like the latest Batman movie; obviously fabulous location; cool new (vintage) concept; moderately priced food; echoes of New York; noise and size. Lots of milling around the spacious bar, low but plentiful deco lighting. Paris, but a user-friendly Paris. Hardly registered on the intimidating scale. Shorts and baseball caps were in evidence. (Philly, way to represent.) On previous nights, Bentleys and Ferraris were dropping off sleek, stylishly dressed dinnerati.

Starr said Parc had been his busiest opening here, with a 45-minute wait for one of 33 outside tables on a weeknight, and serving upward of 1,000 meals a day this week, clearly more than any other city restaurant right now. And this during a downturn and before breakfast starts in two weeks.

Starr said its rollout rivaled the starlet-filled opening of Buddakan in Manhattan in 2006.

Starr - who described Parc as "easy, not fancy" - said he felt the buzz building in recent weeks. "Best thing we did was open the doors [during the last two weeks of construction], and people could look in," he said. "You could feel the momentum build."

But will the buzz last? Not all of Starr's early hits stayed hot. Blue Angel, Striped Bass, Angelina, Washington Square and Cafe Republic have closed.

"This location is so special," he said. "It was asleep for years, a dark corner. Now it feels like a city."

Just like Paris these days, at Parc you can get a burger with your pommes frites. "It's not trendy," said Lisa Buenzle, a paralegal at the bar. "It's like new old."

"For Philadelphia, it's totally trendy," said Katie Balsamo, 29.

Said Marabella: "This place needs to be crowded to get the full effect."

That is definitely true. Earlier in the evening, between rainstorms, the sidewalk tables that seat 80 were only half full. Inside, which seats 210, was three-quarters full.

But when the massive rain at evening's peak sent everyone inside, the place lit up like the summer lightning storm that was, frankly, freaking out 20-year-old Parc hostesses Gabriella DiFulvio and Candace Keeton, stationed outside, drying off intrepid customers with dish towels.

Said Preddy, surveying the post-storm scene over his old-fashioned: "You feel like you're part of something. . . . There's a buzz. There's a lot of nooks and crannies."

Parc, three years in the making in the old Bleu and lobby of the old Sheraton, is authentic enough to catch the eye of the authentically French walking by.

Daniele Thomas-Easton, Philadelphia's former honorary French consul, said she was walking with a guest from the French Embassy this week when they stopped in front of Parc, a bit startled.

"'Look at this,' he said. 'It looks like this wonderful French bistro.' The glass, the announcements outside. It looks so France. They managed to make it look like it's been there for a long time. We looked at the menu to see if they had kidneys."

Kidneys, non. Escargots, charcuterie and duck confit, oui.

"The atmosphere gives you the feeling that you have many options," she said, "including just to sit down, have a drink, do nothing and watch the world."

Meanwhile, at nearby Rouge, Rittenhouse Square's first sidewalk cafe (owned by the daughter of Starr rival Neil Stein), there were no worries. A smaller, more elegant and intimate 1920s style European parlor with chiffon-draped walls, an oval bar and plush seating, Rouge was packed.

Manager Heather Rodky said Parc was welcome. "If anything, business has gotten busier," she said. "It's brought people in. I walked in just to check it out. It has a completely different feel. The acoustics are really loud."

Some regular Rouge sophisticates, she said, had dismissed Parc as a Paris bistro with a whiff of T.G.I. Friday's or, as one couple said before passing, a bit Disney-ish. "This will transport you back to a different time altogether," she said of Rouge.

But at Parc, manager Steve Scott was still catching his breath after being, as they say, slammed 10 nights in a row. "The first day we did 800" people, he said. "I think people are just excited about the concept, how pretty it is."

In the crowd at Parc on Wednesday evening, John Calder, an accountant who would say only that he lives in Montgomery County, captured the spirit of Philly's newest excuse not to go home after work. Asked where he'd be if not at the bar at Parc, Calder said: "On the R5."

Contact staff writer Amy S. Rosenberg at 215-854-2681 or