On our last visit to Paris in May of '07, my wife and I were greatly disappointed that the grass of the Champs de Mars was totally surrounded by chain-link fencing.... is that "art-work" still up and thus prohibiting one of the greatest of Paris rituals.. a pinic under the Eiffel Tower?
As of this past Christmas, yes.
I was there a week ago and didn't see any fence surround the area. However I didn't know that you were ever allowed to sit on the grass in French parks.
Unfortunately, there are too many who wish to have such a delightful picnic in such a beautiful area and the grass patrol can only work M-F and less than 35 hours per week. Thus, the signs and the fencing. Sigh - such a sight. It also is an attempt to keep the dogs business elsewhere given the 200 Euro fine has not been such a deterrent to canine ejection. Do be cautious - it never fails that the day that one rebels and tries out the luscious soft grass is when the Gendarmerie Nationale in all their blue glory happen by with their ticket book.
I would recommend the grass across the river at Trocadero/Chaillot along the hill leading up to the Musee de l'Homme. It has a lovely view as well.
There are also benches and patches of grass along the Quai from Pont Grenelle towards Branly (either direction from the Tour EIffel).
Last July we had several picnics on benches in the same location and thoroughly enjoyed ourselves.
Not sure If i am describing the same area, but we were to the south of the Tower and many locals were enjoying multiple grassy patches/ some shaded, around us.