We are lucky to live a 10-minute walk away from a great food market, the Marche Maubert. It is, in some sense, Paris' oldest market, too. It has existed since the 6th century, originally on the Ile de la Cite, and moved to its current location centuries later when it outgrew its spot there.

The most entertaining interaction by far was with the butcher, a very animated and jovial Corsican. There are considerable differences in butchering practices between France and the US, so the particular cuts of meat that I'm used to buying may not even exist here. There was something that looked like a flat brisket, but I was not sure. I explained (in French) that I wanted a piece of beef that I would cook for a long time in liquid and needed to feed eight people. I figured the butcher would suggest the brisket-type cut. Instead he came back with no fewer than four cuts of beef and demonstrated, using his own body, where on the cow the cuts had come from. I told him that it was too much and pointed to the largest cut he had brought over and said that was enough. No, the rest is necessary, he insisted. You need the bones with marrow and chunks of fat and the pieces of tail for flavor. He said, "Do you want to look at the meat, or do you want to eat it?" He showed me a medal he had won for the quality of his meat and insisted that I trust him. Then he said, with a sly smile, that I needed to look away when he tallied up the total---it was Christmas, after all, and I wanted the best meat for my family regardless of price.
Interesting historical note: Place Maubert is believed to have been named for Albertus Magnus, also known as Albert the Great or Maitre Albert, a German polymath who gave lectures at the Sorbonne in the 13th century. His lectures were so popular, they had to be held outside, in what is now the square named for him and the location of the Marche Maubert. He was a pivotal figure in the intellectual history of the Catholic Church and was considered to be perhaps the greatest intellectual of his time. He was subsequently beatified.