Sweetbread mushroom: Has a farinaceous, flour-like smell.
False champignon: Lacks a distinctive odor or has a slightly fruity smell.
Sweetbread mushroom: Gills are decurrent, running down the stem.
False champignon: Has sinuate to adnate gills, not decurrent.
Sweetbread mushroom: Produces a pinkish-gray spore print.
False champignon: Has white or cream-colored spore print.