l’Annonciade is a 35-storey tower on the hillside overlooking the umbrellas of Larvotto Beach where a three-bedroom apartment with a sea view will set you back north of 10m euro ($16.7m).

But, if investigators in neighbouring France are right, below the surface was a less glamorous reality. They’ve charged Carew, who rented a tiny studio apartment on the building’s fifth floor, with aggravated money laundering and conspiracy to commit serious crimes.

Monaco, too, has a less glamorous reality lurking below its surface sheen of glittering water, pearly white yachts, idling supercars and a resident population said to contain more billionaires per capita than anywhere else in the world.

The tiny territory, just 3.83km long on the sea border and between 350m and 1700 across, is attractive for its unbeatable income tax rate of zero per cent.

Its lax approach to money laundering earned it a string of fail marks in an evaluation by international officials in December, leading the global body in Paris, the Financial Action Task Force, to consider putting it on a warning list that could devastate its economy.

Meanwhile, just across the border - which runs through the street behind l’Annonciade - a powerful French agency tasked with fighting top-level money laundering and organised crime, Junalco, has been crawling all over the French Riviera on the hunt for illicit villas and other luxury assets belonging to an array of individuals, including Russian oligarchs sanctioned over Putin’s invasion of Ukraine.

“Real estate in France, particularly in Paris and the French Riviera, has long been known to attract criminals and the corrupt,” watchdog Transparency International said in a report released this year.

“At the start of the war in Ukraine, some 30 Kremlin-linked individuals reportedly held more than 350m euros ($590m) of French real estate.”

According to French media, Junalco has 19 separate investigations underway into Russian assets and has been looking at targets that reportedly include a villa in Saint-Jean-Cap-Ferrat allegedly owned by the brother of sanctioned industrialist Evgeny Zubitsky and the villa in Cap d’Antibes where Dirty Rotten Scoundrels was filmed, Villa Hier, which is allegedly linked to billionaire Suleiman Kerimov.

Saint-Jean-Cap-Ferrat, a peninsula jutting into the Mediterranean a few kilometres down the coast from Monaco, is familiar territory for Carew and his wife, Anna Polianskaya-Carew.

It’s where the couple were married, at the opulent Villa Ephrussi de Rothschild, and where Polianskaya-Carew’s family owned a less extravagant - but still very nice - villa until 2011.

It is not alleged that Polianskaya-Carew is involved in any wrongdoing.

Junalco, which was set up in 2019 to investigate crimes of “tres grand complexite”, is also the agency investigating Carew and others allegedly involved in the same crime ring.

News Corp Australia can reveal that another person targeted in the same investigation is an Irish-born businessman who ran a real estate business in Dubai at around the same time as Carew worked in the property sector there.

The Irishman’s business interests include companies around the world that offer services to the ultra-rich such as organising to buy luxury goods including sports cars and jet planes.

He “is implicated in the context of the judicial investigation concerning counts of aggravated money laundering, customs money laundering and association of criminals with a view to the preparation of an offence punishable by a 10-year prison sentence,” a French judicial source said.

However, he has not been charged with any crime or arrested and there is no suggestion Junalco’s allegations are true, only that it is investigating them.

He could not be reached through business associates or at a personal email address associated with one of his companies.

Back in Monaco, it’s not clear if any of Carew’s business ventures had anything to do with the money laundering charges against him, or whether they amounted to much at all.

l’Annonciade was the address he used to set up his Monaco real estate business, BCR International, in 2017.

Carew also used the address on paperwork for one of the UK companies he ran, Sterling Estates International - a venture with his sister, Natalie, who lives in Australia that was also set up in 2017. There is no suggestion Natalie Carew has done anything wrong.

The Australian man also set up a Latvian company, Carew Private Equity Fund, in 2019, and another UK company, Meru Group, the same year.

Meru was supposed to be a partnership with Dubai-based tech entrepreneur Paul Kenny, set up in pursuit of a deal to buy agricultural produce.

“By the time the company was set up he disappeared and he never answered his phone or from what I remember his phone was disabled,” Kenny said.

“So my few conversations with him lead to nothing.”

Kenny is not alleged to have engaged in any wrongdoing.

There were also struggles with the French banks, who refused Carew a loan four years ago.

“He was angry, he said he wanted to expand his business, he was in real estate, he told us, but the banks were blocking him,” a source said.

BCR was wound up in 2020, Sterling Estates and Meru Group were struck off in 2021 and Carew Private Equity Fund was removed from the Latvian register in March last year after failing to pay its taxes.

According to security staff at l’Annonciade, the Monaco apartment was used to meet business contacts and crash out when Carew was “drunk and it was too late to drive home to La Turbie” in France, where he and his wife lived.

And it wasn’t corporate paper-shuffling that led to Carew falling into the Junalco spotlight.

Monaco’s porous boundaries - there are more than 50 land crossings with France, including the street behind l’Annonciade, and none of them have border controls - make it vulnerable to cash-running.

Once inside Monaco, money can be deposited into a bank or used in the principality’s network of wealth management companies - which authorities say do not properly grasp the risk of money laundering - to disguise the cash.

It was the folding stuff that was Carew’s downfall. Sources say firefighters found him drunk and injured by the side of a Paris street in late 2021.

They searched his bag and found almost 200,000 euros ($335,000) in cash. Another 160,000 euros ($270,000) turned up when police searched an AirBnB in Paris where he was staying, and investigators believe he handled about 4m euros ($6.75m) in cash and through his bank accounts in 2021 alone.

The Junalco investigation continues, but has been overshadowed by charges of attempted murder after Carew allegedly tried to kill his wife at the La Turbie villa in April.

It’s a twist that has left those who had business dealings with him in distress.

Kenny said he never met Carew in person but was “shaken” by the news.

“He seemed like a normal person on the phone when we spoke years back - this is very sad to read,” he said.