  We have observed hysteresis in superconducting resistive transition curves of
Ba$_{0.07}$K$_{0.93}$Fe$_2$As$_2$ ($T_c\sim$8 K) below about 1 K for in-plane
fields. The hysteresis is not observed as the field is tilted away from the
$ab$ plane by 20$^{\circ}$ or more. The temperature and angle dependences of
the upper critical field indicate a strong paramagnetic effect for in-plane
fields. We suggest that the hysteresis can be attributed to a first-order
superconducting transition due to the paramagnetic effect. Magnetic torque data
are also shown.
