But the privacy was an illusion, the special dining room a trap.
For about a year, waiters secretly recorded public officials at Sowa & Przyjaciele and another restaurant. When a newsmagazine published transcripts from some of the recordings, it spawned a scandal dubbed "Waitergate" that helped topple a pro-European Union government.
Suspicions that Russia and the nationalist political party that won Poland's 2015 election were behind the illegal eavesdropping persisted even after a Polish multimillionaire was convicted as the mastermind. With the country's next election coming up this fall, a Polish journalist and the jailed tycoon have provided fresh fuel for claims that Waitergate was a prelude to Russian interference in the 2016 U.S. presidential election.
Grzegorz Rzeczkowski, a respected investigative reporter for the Polityka newsmagazine, argues in a new book that Russian intelligence services carried out the restaurant buggings on behalf of the Kremlin. He also presents evidence to allege that Polish intelligence figures conspired to use the recordings to bring the right-wing Law and Justice party, or PIS, to power.
In his book, titled "In a Foreign Alphabet: How People of the Kremlin and PIS Played with the Eavesdropping," Rzeczkowski maintains that, just as with the U.S. election meddling that special counsel Robert Mueller called "sweeping and systematic," Russia's goal with Waitergate was to weaken the West.
"It was to open the road to power for the anti-Western, anti-liberal, anti-democratic opposition of the time," Rzeczkowski told a Polish parliamentary panel last month. "Russia had a full, spectacular success."
The panel stemmed from an opposition lawmaker's push to pressure the government to shed light on the alleged Russian connection. A newspaper subsequently reported that Poland's counter-intelligence service is investigating whether a foreign spy agency played a role.
The Russian Foreign Ministry has dismissed claims of Kremlin involvement.
"Poland's political establishment and media community have been working for years to put out a multitude of hoaxes about 'Russian machinations,'" the ministry said. "We see no need to comment on such absurd allegations."
A wariness that Russia is trying to destabilize democracy in central Europe has permeated politics in Poland and neighboring nations since they ended communism after decades under Moscow's control. Many have since joined NATO and the EU while more have applied.
When the eavesdropping scandal broke five years ago, then-Polish Prime Minister Donald Tusk immediately pointed to Russia. His remark would give Rzeczkowski his book title: "I do not know in which alphabet this scenario was written, but I know exactly who could be the beneficiary."
Tusk became president of the European Council several months after the scandal unfolded, a job that involves overseeing the common agenda of the EU's national leaders. He recently said he was more convinced now of "the Russian track in this whole affair."
The coal tycoon's arrest in Spain and recent extradition to Poland has added to the intrigue. Polish prosecutors accused Marek Falenta, 43, of recording the politicians to punish the government for trying to block imports of Russian coal. He fled before starting a 2½ -year prison sentence.
After his capture, Falenta threatened to expose Law and Justice members for allegedly recruiting him in the recording plot if he didn't receive a presidential pardon, according to letters leaked to Polish newspapers. He told the president, prime minister and the powerful ruling party leader he expected better treatment in return for helping them.
Government officials have called the letters an act of desperation from an untrustworthy source. They refused to respond to requests by The Associated Press for comment on the allegations of Russian responsibility for Waitergate.
Dozens of politicians had hundreds of hours of conversations illegally recorded at the two restaurants between June 2013 and June 2014. Poland's government, led at the time by Tusk's centrist Civic Platform party, had declared a fight against Russian coal imports and was a strong advocate for the Western course that activists were agitating for in Ukraine.
The leaked recordings proved deeply embarrassing for Tusk's government. One of the first captured the foreign minister complaining that a "bullshit" alliance with the United States put Poland, metaphorically speaking, in the position of performing oral sex.
Under the conservative Law and Justice government that came next, Russian coal imports have doubled. Signs of democratic backsliding, such as government encroaching on the independence of Poland's judicial system, have caused tensions with the EU. Warsaw has almost ceased to be an advocate for Ukraine.
Radek Sikorski, the former foreign minister caught grumbling about Poland's alleged deference to the U.S., resigned along with three ministers four months before the 2015 election. Now a European Parliament member, he openly criticizes American officials for not taking Waitergate as a warning.
"We were a laboratory for what happened in the United States, and the U.S. was too arrogant to take heed," said Sikorski, who says Russian hacking group Fancy Bear sent him one of the emails that would compromise Democrat Hillary Clinton's presidential campaign in 2016. "'We saw it coming. It was successfully tested in Poland."
Central to Rzeczkowski's theory is the former manager of Sowa & Przyjaciele, who waited on officials in the VIP room. Referred to only as Lukasz N. because of Poland's privacy law, he previously managed another Warsaw restaurant located across the street from the U.S. Embassy.
Lemongrass was established by the director of the Polish branch of Russian energy giant Lukoil with money from Russian organized crime, according to Rzeczkowski. He says counterintelligence sources told him the restaurant was a front to spy on Americans and when the cover story was blown, two Russians bought the place.
Two other businessmen with Kremlin connections opened Sowa & Przyjaciele in 2012 in cooperation with star chef Robert Sowa, the journalist says. The manager, Lukasz N., sent Polish politicians text messages inviting them to sample Sowa's modern European dishes.
Rzeczkowski says other alleged links between Sowa & Przyjaciele and Russians in organized crime suggest a Polish tycoon did not organize Waitergate.
Polish media reported last year that Falenta had a multi-million dollar debt to a Russian coal company, KTK. A leading Polish police investigator on the recordings case got a top security job at KTK — after saying early on in the probe that he found no evidence of Russian involvement.
Tomasz Piatek, another journalist who investigates links between Polish political figures and Russia, says Rzeczkowski's evidence is overwhelming, but he thinks fear and denial keep the truth about Waitergate from getting the attention it deserves.
"It's a reason for pride for Poles to say we freed ourselves from Russian domination," Piatek said. "To admit that Russians are still here and that we are still controlled by them is hard."