"Superb fruits de mer..."
I have this place lined up for some Gillardeau oysters after/before a visit to Sacre Coeur. BUT, I am also narrowing down the choices for un plateau fruits de mer. Should this place be on that list? I want the best food for the best value... I can't find a carte for La Mascotte - only the very sweet and inviting narrative on the website. Do you know the price point for a plateau? Also, if I could get opinion on how would it compare to the others I am considering:
Bar a Huitres 49euros - includes Belon oyster - so expensive, must try at least one!
Rech 35 euros -looks like an amazing place to be, plateau seems a great bargain, and highly recommended
La Rotonde 21 euros - "assiette" - awesome price, not so abundant
Sorry for the thread hijack....
I may have the advantage because I'm French and can talk waiters into customizing my plateau of fruits de mer to accommodate my tastes and my budget. But I wouldn't think it's that difficult for a tourist to negotiate in the same way. For la Mascotte, you can probably count on 40€ for a perfectly adequate plateau for 1. And you can browse the selection and prices in the écailler annex before you go into the restaurant and then present the waiter with a list of the items you want on your plateau (probably a 20% mark-up between the takeaway prices at the écailler and what you will be charged in the restaurant). At Rech, the 35 € plateau sounds suspiciously cheap for such an expensive restaurant and I suspect you are quoting the price for a much smaller "assiette". The Bar à Huîtres plateau at 49 € is quite large and includes a whole (smallish) crab. It's the only place where I have great difficulty in persuading the waiter to customize my order so, if you can't be flirty and cajoling in French, you would probably be stuck with a standard plateau from the menu. The 21 € assiette de fruits de mer at La Rotonde is pretty skimpy but they do throw in a crevette or two. Their full plateau runs around 90 € but way too much in quantity and price for just 1.
When comparison shopping, be careful not to confuse apples and oranges. An "assiette" will always be an abbreviated selection and most will only include a sample of clams, oysters, winkles, etc with, occasionally, a prawn or two to amuse the bivalves. A "plateau" is usually quite a festive and artsy arrangement of a large selection of molluscs and crustaceans. Pricing can also be confusing. Most pleateaux are designed to be shared but are often priced per person. So let's hope your waiter knows English sufficiently well for you to negotiate a plateau for one.
It's impossible for me to choose "the best" place. I like La Mascotte a lot because the prices and the ambiance are very pleasing. But even though I'm usually motivated by "une valeur sûre" rather than just quality, I gotta say that that I'm also a big big fan of the more expensive Rech. Convenience/ proximity, however, trumps all. If I'm near the 17th to meet friends or go to the cinéma or theatre, Rech it is. If I'm visiting my sister in the 18th, it's La Mascotte. If I'm just hanging around my own quartier, it's Bar à Huîtres or la Rotonde. You should also add l'Ecailler du Bistro on the rue Paul Bert in the 11th to your list. Not sure of the price for 1 but as a benchmark the standard plateau (easily enough for 2) is around 60 to 70€.
Gillardeau is sold in very few poissonneries in Paris, and La Mascotte is one of those places that have it.
In general La Mascotte is not an expensive place. Just bear in mind you are getting the most expensive of oysters.
The cheapest good-quality oyster bar we have found is Pleine Mer. But be prepared to wait for the owner-waiter-chucker one-man-band, in a very no-frill interior.
It is not in the 18th, which is where OP asked about.
I will go back to the OP if you don't mind. Sunday is a day when many restaurants close. Plus Montmartre, even on a non-Sunday day, is already full of tourist-geared eateries. One must be careful with the very limited choices of restaurants. La Mascotte is a great option that reconciles large-party accommodation, good food, location as specified by the OP.
Lastly, with seafood, especially raw oysters, even this queen of cheap would prioritize quality over budget.
Most Montmartre restaurants are rather small, you might think of L'ete en Pente Douce. There was a party of ten last time I went although they were not very pleased with the service which is, unfortunately, very hit or miss (the food's great though!) There are plenty of restaurants on Boulevard de Clichy which are larger and could accommodate you.