I actively searched for Berthillon on the Ile St Louis after I had heard such magnificent things about it. What I did not expect was to find most of the cafes on the island advertising that they sold Berthillon ices. As I had no idea where the original shop was or what it looked like, I was constantly fooled by these vendors.
During a relaxing lunch of a citron presse and a croque madame in a cafe, I realised that ice cream cones were being carried from a certain direction. When I'd finished and paid up, I walked towards that direction, and there it was!
A peek through the little window open to the street showed a lady sitting on a chair and a freezer next to her with all the ice cream sitting inside. There appeared to be a cafe within the shop but it was closed, presumably since it was November. Next to the window was a multi-coloured display of the various ice creams available--new availabilities were added on a hand-written slip of paper posted to the menu. I was glad this menu was large, as I took much time deciding what exactly it was I wanted--a decision also based on how much my stomach could handle!
Finally, I stepped up to the window and ordered. I wanted a two-scoop cone with praline aux pignons (praline with pinenuts) on the bottom and cassis (black currant) sorbet on the top. The cone is a very long and thin waffle cone--I vaguely remember choosing this cone for a slightly higher price--and normal wafer cones were also available. I think I paid approximately €4.
The praline was average--a very creamy and rich with caramelised pinenuts. The cassis, though, was extraordinary. Slightly tart, it tasted of black currants more than black currants themselves could taste! Delicious! The balls of ice cream are smaller than one would normally expect in the UK or North America, but the flavour coming from them is 10 times that in return.
From what I did try, I would recommend sticking with the fruit sorbets, as their flavours are amazing. However, I wouldn't mind going back to try *all* the varieties of ice cream and sorbet on offer.
They have a website at http://www.berthillon-glacier.fr, where it states that they are closed on Monday and Tuesday.