It’s not just the size that takes the breath away, though any cellar that stretches out across 1.5 sq km is bound to do that. It’s not even the number of bottles – 350,000 in total, spread across a maze of different corridors. No, rather it is the unceasing wall-to-wall quality that unfolds before your eyes – one fabled name after the next. Domaines Rousseau, Leroy, Coche-Dury and Comtes Lafon; Clos des Lambrays, Clos Vougeot; Château de Beaucastel, Guigal, Chave, Jaboulet; Krug, Cristal, Dom Pérignon; Mascarello, Quintarelli, Gaja, Sassicaia; Dagueneau; Vega-Sicilia… And I haven’t even got on to Bordeaux. 

And the vintages – oh, the vintages. Sure, you expect to see the odd first growth and prestige cuvée in a hotel of this quality, in this location – but we’re not talking just a couple of bottles of Haut-Brion from a mediocre year. (Indeed, come to think of it, I don’t spy much 1994 Bordeaux or 1984 Burgundy knocking around.) Instead, I count 88 bottles of Cheval Blanc 1990; 72 of Petrus 2000. There’s first growths from 1961, ’59, ’45 – and more…

The collection spans 4,200 different listings, taking in Bordeaux crus classés (a third of the total list is claret), Burgundian grands crus, California cults, Super-Tuscans, Rhône royalty and curiosities from further afield. There is even an enterprising offering of Lebanese, Israeli and Syrian wines. You name it, you’ll find it. 

The cellar dates back to 1874, when, just ten years after François Blanc opened the hotel, his enterprising wife Marie set her mind to developing a cellar she felt was fit for the discerning clientele she hoped to attract. Over the course of two years, she employed – from her own personal funds – 100 workers to dig more than 30ft down into the Monaco rock to craft this gargantuan temple to Bacchus. The layout – and masonry – has remained unchanged since; right down to the wooden trolleys still used by staff today to wheel bottles around the neatly ordered, heavily laden corridors, themselves identified by the same hand-painted script on their walls. 

The tone is set immediately on emerging from the lift that cuts through the rockface. Stack upon stack of classed-growth Bordeaux are piled high in the entrance – 2005 Cheval Blanc, Ausone and Canon-la-Gaffelière – all still in their original wooden cases, undisturbed since the hotel took receipt of them 12 years ago. ‘We’re waiting for the right time [to open them],’ I’m told. All the wines are bought direct from the châteaux – at the behest of the cellar’s tasting committee, which travels to Bordeaux to taste en primeur every year – then delivered to age here after bottling. 

As a result, the hotel is sitting on a vinous treasure trove. Some 300,000 bottles a year are brought to the surface, including more than 100,000 bottles of Champagne, to one of the 22 restaurants that come under the banner of the hotel’s owning Société des Bains de Mer. They might be destined for gastronomes patronising Alain Ducasse’s three-Michelin-starred Louis XV or the conspicuous consumption of A-listers’ favourite hangout Jimmy’z or, of course, the high-rollers of the Casino de Monte-Carlo. And should the constant flow of guests’ yachts into the Monaco harbour ever dry up, the group could always turn a quick profit from the discreet sale of a few cases of 1990 Petrus or Le Pin. ‘It’s true,’ says Gennaro Iorio, the long-term cellar master. ‘And we have clients who want to buy – we always have requests. But we have to tell them no. This is not a cellar for short-term profits.’

It has been through too much for that. At the outbreak of the Second World War, in advance of the German occupation, the staff closed off a section containing the most prized cuvées, blocking its path by littering it with empty broken bottles. The ruse worked; the cache survived. Prince Rainier III reopened the room in 1947 with a party; three decades later, he and his wife Grace Kelly held a celebratory dinner for their 20th wedding anniversary there. Today it is home to the most prized vintages. Or perhaps the second most. For while the Hôtel de Paris may regularly host royals and oligarchs, heads of state and Hollywood A-listers, not even the starriest of guests have access to the cellar’s Réserve Patrimoniale. 

This ultra-elite collection, hidden away under lock and key in a remote corner of the cellar (also known as the Marie Blanc museum, though it’s not open to the public) houses the hotel’s rarest, most prized bottles, none of which is for sale: Yquem 1890, Moët & Chandon 1923, Margaux 1934, Mouton 1945, Latour 1953… So what happens if Prince Albert asks for a bottle of DRC Richebourg 1971 for a special occasion? ‘We tell him no,’ says Iorio. ‘It’s important to preserve such treasures for future generations, for posterity. I think of this as a monument.’ 

Iorio has worked at the Société des Bains de Mer group for 32 years, having joined as a waiter. He has been cellar master at the Hôtel de Paris Monte Carlo for 21 years. How have tastes changed in this time? ‘The consumption of Burgundy, especially reds, has increased considerably. Champagne, too.’ Iorio reports declining interest in older vintages, particularly Bordeaux; he puts this down not so much to taste but to a ‘different culture among the younger generation’. So, is there anything he doesn’t have in the cellar that he would like? He thinks for a moment. ‘There are a few bottles of Henri Jayer that would be nice.’ 

And with that, he picks up his spirit level and heads off to check that everything is as it should be on the shelves of Alsace grands crus.