Can I eat only a crème brûlée in Paris?

You're overthinking it. We're french, weird but not that much. Just walk in any restaurant, order anything you'd like, would it be just appetizers or a dessert, pay your bill and walk out. I would be happy to show you how it's done. :)

Enjoy your crème brulée (it's not that great though) !

France has something called "Le Goûter", which is their version of Afternoon tea. The French generally eat late in the evening, after 8 PM, so there is a habit of having something sweet in the afternoon to tide you over between lunch and dinner. This is a fully socially acceptable part of their diet and is viewed not as a snack but as a meal in the own right, a point of the day for socializing and meeting friends old and new.

If you can find an open restaurant or brasserie around 4-5 PM willing to serve a crème brûlée with a cup of coffee, that's actually fully socially acceptable. You'll probably not even be the only one in the restaurant doing it. If you got any friends along with you, feel free to invite them along.

Once in Lille, France, we went only for desert, since it was not dinner time yet, and we were on holiday, to a restaurant that was fancy enough to have a table d'hote menu, but not fancy enough to not to have an a la carte menu. So we ordered dessert, but we really took our time to enjoy it. By now it was dinner time, but we just ate some dessert, so we decided to skip first course and just go for the second course, and not for the full menu. The served duck was amazing, to the point we decided we need to taste what they have as a first course. Again, an extraordinary soup. We decided to end our culinary experience with the drink everyone seemed to be enjoying in the restaurant at the time. The waiter informed us that that's a wine they serve as an appetizer, but he happily obliged. Yes, we managed to order separately, the full table d'hote menu, in the exact opposite order, and I regret nothing because the food was amazing.

If we managed to do that, you'll be fine simply going for dessert. And based on my experience, you'll also be met with great service.

I suggest looking at the Brasseries (Bonfinger, Julien, La Coupole ... ).

They will all have Crème Brulée.

As Nate wrote, just go in and tell them you are there for desert only (desert, coffee, digestif).

BTW, I'm surprise that patisseries in Paris do not sell single portions Crème Brulée.

First, find a restaurant with the crème brûlée on the menu and which is open when you would like to visit. Next, simply announce that you are there only for dessert when you are greeted by the host. "Seulement du dessert," and "Ç'est ça va?" or "Acceptable?"

When you enter any business (retail, restaurant, etc.) in Paris you are expected to make eye contact with the proprietor or representative and greet them. In the restaurant this is an appropriate time to announce your intentions, so that the host has a chance to say, "No, it is too busy now if you are not having a meal," or "would you please sit in the bar area instead of at a table," etc.

I am a French student/part-time worker. During one of my internships, our CEO invited us into an Italian restaurant once for noon within Paris. Despite the fact that I had already eaten my meal at the office, he still asked me to come for dessert.

At the restaurant, both him and my colleague took a meal and a drink, but all I took was a waffle with cream and caramel. And we all got what we ordered.

You might personally feel awkward, but they didn't say anything. They simply took the orders.

Restaurants may not accept to serve you only a dessert if they are short on tables and there are people waiting for a free table to have a complete meal. Cafés, on the other hand, usually don't expect all their customers to have a meal: they typically serve drinks, snacks and desserts separately. Having said that, you may actually want to order your crème brulée in a restaurant of your choice, to make sure you get a good one.

Typically, if you see empty tables, there's a good change you will be able to order only a dessert without a problem. In a busy restaurant, it's a good idea to ask if you can only have a dessert in advance. If it's not possible, don't hesitate to ask when would be a good time to come: most restaurants don't stay full the whole day, and the waiter should be able to tell you at what time you are likely to get your order accepted.

Some patisseries do sell crème brûlées, e.g. patisserie Stohrer:

Not only crème brûlée - there's a whole class of entremets froids you're not likely to find in many bakeries or takeaway places. Mousse au chocolat, riz au lait, flan (the sort without crust), île flottante come to mind.

Though the reason is not immediately obvious, my guess is that their consistency doesn't allow easy transportation in the common cardboard boxes used by these shops, let alone eating them on the go with your hands. They are more usually consumed in round glass or ceramic receptacles - in the case of crème brûlée often the same one it went to the oven in.

Possibly, the fact that you would have to demould each item to put it in another, same sized container is an additional limiting factor for crème brûlées.