Hello,
Above all, thank you to excuse my bad English.
J have found this species in a park under a willow, in the North-East of France.
Largest has a hat diameter 105x100mm; the height of the foot 75mm, diameter 65 X 40mm.
Without particular taste, those release in all the part a strong unpleasant odor, naphthaline kind.
Its consistency is a little rubbery, with traces of cortine.
It is deprived of ring, bulb and volva.
The spores are brown rusts, 10x5.5µ.
Thanks a lot
Not a Champignon (i.e., Agaricus sp.): Agaricus has a darker, chocolate-brown spore print and a ring on the stipe among other things. You have a species of Cortinarius.