HIDDEN GEMS: WHAT HAVE Harry Potter and a modest little restaurant in the Marais, an old quartier of Paris on the right bank of the Seine, got in common?
The answer is Nicolas Flamel, the 14th-century alchemist, whose major work, Exposition of the Hieroglyphicall Figures,was published in Paris in 1612.
Flamel and his wife, Pernelle, are reputed to have discovered the philosopher's stone, reputedly capable of turning base metals into gold and holding the key to immortality.
The extraordinary thing about such an esoteric piece of information is that you're far more likely to take it for granted if you're an attentive reader of the Harry Potter books. Flamel and his wife, by now aged 665 and 668, appear in the first of the series, the aptly named Harry Potter and the Philosopher's Stone. Flamel is also mentioned in The Da Vinci Code.
What neither JK Rowling nor Dan Brown reveals, however, is that the real Flamel lived at 51 Rue de Montmorency, a tall crooked building dating back to 1407, when he and his wife opened it as a hostel for the poor.
Today, apart from being the oldest house in Paris, it's a bistro, Auberge Nicolas Flamel, that serves wholesome food and wine, doesn't appear in any Paris guidebook and basically keeps itself to itself, much as Flamel once did.
Still, a visit is a pilgrimage for anyone who relishes the byways of history. The street is dark. The restaurant is rarely full. Thankfully, there is no memorabilia.
My wife and I visited with friends for a 60th - not a 600th - birthday last year. The food was okay. But the atmosphere was magic.
• Auberge Nicolas Flamel, 51 Rue de Montmorency. Paris, 00-33-1-42717778, www.auberge-nicolas-flamel.fr
• Do you know of a hidden gem? E-mail us at go@irish-times.ie