  We present ISOCAM images (1.5"/px) in the LW2 (6.75 microns) and LW3 (15
microns) broad band filters of the circumnuclear starburst of NGC 4321 (M 100).
A detailed comparison with the emission at other wavelengths (U, B, Halpha, and
CO) is also presented. The nature and intensity of the mid-infrared emission is
shown to be remarkably different from one star forming region to the next. For
instance, star forming regions at the ends of the nuclear bar may contain
enshrouded Wolf-Rayet stars.
