We present microvariability observations of OJ 287, taken during a small flare in January 1994. We can follow the behaviour of OJ 287 during the whole flare. The event has a synchrotron flare shape, with a steep ingress and slower egress, and a double peak structure most likely due to two similar flares occurring a day apart. Microvariability is observed on top of this flare during at least six nights, out of ten. Two types of microvariability events can be identified: small flares and smooth sinusoidal variations. The time scales are of the order of minutes to hours. We do not find any periodic or quasi-periodic variations. A brief discussion on the possible mechanisms responsible for the different scales and types of variability is given.