The nightclub, the M2 UltraLounge on West 28th Street in Manhattan, went on trial last week at a special administrative court that the city uses when it seeks to take away property. If the case against the club succeeds, it would be the first time the city had closed a business solely for flouting a ban on smoking. City officials have also moved to take several other clubs before the court, seeking to revoke their food and beverage licenses. It has been an open secret for years among the late-night set that there is a network of so-called smoke-easies throughout the city, from little neighborhood dives to glossy, exclusive boîtes, that let patrons smoke illegally. Health department officials say that the vast majority of businesses comply with the 2002 law forbidding smoking in clubs and bars, but that inspectors have struggled to enforce it at a handful of high-end places that seem to market themselves as smoker-friendly, some even offering loose cigarettes for sale. Generally, health officials have looked for signs of active tobacco use as part of their inspections concerning other rules, like those for food safety, and have cited clubs for violations that often result in fines of $200 to $2,000. But they have had difficulty gaining access to the clubs when patrons are actually smoking. “Some of the clubs where smoking is going on tend to be very, very cool clubs, and a bunch of guys showing up in jackets tend to be very, very uncool,” said Thomas Merrill, general counsel for the health department. So in recent months, the department has deputized a team of inspectors — many of them younger and hipper-looking than the stereotypical bureaucrat — to work into the wee hours, posing as patrons and hunting for tolerance of smoking by clubs’ employees. Because the inspectors found many instances of patrons smoking without being asked to stop, the department petitioned the administrative court, the Office of Administrative Trials and Hearings, known as OATH, to recommend revoking the food and beverage licenses of 16 bars and clubs.