There isn't much conspicuous consumption around at the moment. In fact, conspicuous non-consumption is more prevalent. For example, the government's announcement, after the last election, that it was cutting back on ministers' cars was as much about being seen to save money as buying a personalised number plate is about being seen to spend it. These days all organisations, and most people, want to appear parsimonious. If you're not tightening your belt, you might be caught with your trousers down.

In financial terms, ministers forgoing their cars is practically unnoticeable. It was projected to save £2.8m a year, which is peanuts ("If I had a pound for everyone that comment has just annoyed…" as Jeremy Clarkson's contract reads). Of course it's a lot of money for one person, but, divided up among all 60 million of us, it's about four and a half pence, which would buy you roughly 3g of peanuts from a supermarket. I don't know how many peanuts that is, but then I work in the media and have no idea about normal people's lives.

Anyway, it won't even save that much, because while ministers are taking public transport, their red boxes still have to be chauffeur-driven in case the minister gets forgetful or mugged, and the time and venue for the next News International drinks bash falls into the hands of a vagrant on the Circle Line. So it may only save 1 or 2g, which is probably just peanut.

The fact that our leaders are willing to undergo great inconvenience to such minute fiscal effect is a sign of how highly they value appearing money-conscious. No one sensible begrudges them those cars, but someone must have calculated that the publicity reward for dispensing with chauffeurs is worth every single journey any minister ever takes being less convenient and pleasant than it would otherwise have been.

In that context, Nicolas Sarkozy's decision to install €75,000 ovens – proper ovens you can actually roast things in, not microwaves – into his new presidential jet is all the more puzzling. They were just one of the expenses that reportedly added over €200m to the €55m it cost to buy the aircraft. Which is more than peanuts. It's olives, at least. Possibly even platter-of-cheesy-nachos.

What was he thinking? No aeroplanes have ovens. Even billionaires who Learjet around the world in mega-opulence have come to terms with the fact that, for the few hours of the flight, they'll have to make do with cold or microwaved food. Multi-millionaires, who always turn left on boarding and drink only Fiji Water and vintage champagne, still accept that a baked Alaska is something they'll just have to look forward to on landing. No one's proposing that Sarkozy should take a cramped train home every day alongside people whose jobs he may have just cut. But would it not be worth his enduring a few hours without fresh croissants in exchange for not looking like a pampered dick in the press?

Soup, Nicolas! Have you not thought of soup? Perfect when microwaved – you're much less likely to over-boil and thus impair the flavour. Many people choose to eat soup even when not on a plane. It can be pre-prepared to the very highest standards - the finest bouillabaisses and consommés ever known to the stratosphere – and there'd still be change from 75 grand. And 75 grand for an oven? Don't think, by the way, that that figure includes installation. That would explain the large amount, one might guess – making an oven safe to use on an airliner is the really expensive bit, one might presume. One would be right – that cost a further €1,004,557.

I mean, on the one hand, sod it – he's the president of France, he's fitting out a new jet, he might as well make it posh. But on the other, why ovens? It's such an avoidable political risk. Maybe it slipped through without his noticing, in an unguarded moment as he looked adoringly up at his wife – but that seems unlikely because there's no moment in the standard airliner-luxury-refit conversation when the guy who's organising it says: "And of course then there's ovens – shall we just go with the 75 grand set? Great – now, plunge pool."

Perhaps things feel very different across the Channel because over here the Queen is having to borrow a car park millionaire's yacht for her diamond jubilee. That's a monarch, an entirely ceremonial figure, someone who is supposed to seem all rich and gilded, our country's very own embossed little calling card, and yet the fashion for outward displays of thrift is such that even she cannot be seen to have her own yacht, or to spend public money hiring one. "We can't have people yachting around at the nation's expense every single time they've been on the throne for 60 years – it's unsustainable!" seems to be the reasoning. Meanwhile, her French counterpart has commissioned the only plane in the world in which you can make Yorkshire puddings.

I don't think France is any less screwed than us economically – they'll be paying for Greece for a hundred years. So the only conclusion I can draw is that Sarkozy thought that the ovens, like L'Oréal's airbrushing costs, were worth it – worth the money and worth the political fallout. And still people say he's no gastronome. On the contrary, he's nearly average height.

Last week's other 75 grand extravagance was in pounds. Restaurateur and sommelier Christian Vanneque bought the most expensive bottle of white wine in history and said, on the subject of its potentially being corked: "I hope not, my God." Which means, I realised with a shudder, that he must be intending to drink it. If he does, and it hasn't gone off, it should taste, as wine critic Robert Parker approvingly put it, like "liquefied crème brûlée". Yuck. And if that's what you want, wouldn't eggnog be cheaper?

But I love that Vanneque believes that, if the wine's not corked, it'll be worth the money. In his mind, for a really nice drop of wine on a really special occasion, £75,000 is a fair price. He hasn't forgotten the value of money, he's just massively into wine. He plans to open it in 2017, the 50th anniversary of the start of his career, at the restaurant where he first worked as a wine cellar assistant, and invite his wife and brother to consume it with him inconspicuously. I like his style, but I can't say I'd want to buy him a drink.