Hi. We will be there the first Sunday in May and would like to take advantage of this. Any idea which museums are included? Thanks

I have a guidebook (Hunter Rivage Paris and I'le-de-France) that says that the Louvre is free the first sunday of every month. I did not see this on the Louvre website though. Perhaps others will weigh in..

Paris fans can help -- my information and experience is that the national museums are open and free on the first Sunday of each month. There are city museums, however, that may not follow this practice. The Louvre and the d'Orsay, for examples, are national museums.

Free comes with a price - huge crowds at times reportedly negating the experience at these (Louvre, Orsay) already often teeming museums.

The Louvre is one of the free museums, and it is absolutely packed. Get there early if you plan to take advantage. If you are going to be in Paris a few days, I would advise purchasing the museum pass, which gets you into just about all of the museums in Paris. That way you can go on the non-free days when they are a bit less crowded. The museum pass can be purchased at metro stations, or the museums themselves. If memory serves me correctly, you can purchase a 3 or 5 day pass.

We visited both the Louvre and the Musee d'Orsay on the first Sunday of last June, when both were free. We spent a half day in each museum, which was perfect for us to see the highlights at both. I was concerned about overcrowding, which proved not to be the case. Each museum was about as crowded as I'd expected it to be on any given day, no huge throngs on our free Sunday. Very manageable. Try entering the Louvre by the underground entrance way. It is supposedly less populated.
I was also concerned about seeing them both in one day. But we're not avid museum-goers, we prefer to be outside seeing the architecture of a city, so this one Sunday worked fine for us. Since you'll be there in May, I'm guessing it might be even less crowded than in June, since most tourists aren't there yet. Be sure to have a map of the Louvre, and mark on it the artwork you must see, because it is such a large museum. And the Louvre building is beautiful in itself, you can easily get lost. I believe these museums are always free admission:
City-owned ‘museums’:
Balzac's House: 47 rue Raynouart
House of Victor Hugo : place des Vosges
Vie Romantique : 16 rue Chaptal
Musée Carnavalet - Histoire de Paris, close to the Pompidou
Enjoy Paris.

everyone, thanks alot. this will be our third trip to paris. i figured this way i'd only have to buy the (new) 2 day museum pass if i can get either the orsay or lourve covered on sunday. if not i'll get the 4 day pass.

PalQ is absolutely right. The crowds are awful. After experiencing the Louvre and the d'Orsay on first Sundays we avoid the free entries like the plague!

I am going on March 3rd through 12th. Would the issue about sunday crowds be true at this time of year too?