I travelled in November 2014. I recommend purchasing the Eiffel Tower tickets ahead of time, BUT you have have poor weather. In November, we did have to stand in line, I cannot say how long, perhaps around an hour, but the people watching was great!
At the Louvre, we waited in line for a short time; I could not find the underground entry as recommended by Rick. We waited at the entry where the Pyramid is, so we were surrounded on 3 sides by the beautiful building, again, not a problem at all.
I love the open air markets. I suggest the work a day one of Grenelle, which is right under the elevated Metro; it begins at the Motte-Piquet Grenelle metro site. There is a great Monoprix there with a grocery in the basement. A finer market is the President Wilson, which is across the river from the Eiffel Tower on President Wilson Avenue. You will have to google the dates, they are twice weekly. There are other markets around but I know those 2 well.
Rue Mouffetard (? Spelling) is fabulous; it is a street of small food shops and cafes; there was dancing at the base of the street on Sunday morning. There is a smaller market at the Place Monge, Monge metro stop (twice weekly).
A fun thing about going to the market is picking up food for a picnic; in November we had some warm days and you might have that in February also.
I also love the Luxembourg Gardens; they were interesting in November. It is likely they will still be lovely in February.
Enjoy