The aim of this work is to investigate the possibility of the magnetic breakout scenario (Antiochos et al., 1999) for the July 14, 1998 flare. Mees vector magnetograms show that the flare occurred right above the sheared portion of the neutral line surrounding a delta-spot. A potential magnetic field extrapolation from a Kitt Peak line-of-sight magnetogram reveals the presence of a 3-D null point above the delta-spot. The flare was observed by TRACE in the 171 Å line, with a 1 minute time resolution and 0.5" spatial resolution. These observations show in particular the opening of some loops prior to the flare, indicating it was an eruptive flare which probably led to a CME. We show that the evolution of the observed features during the whole event, combined with the location of the null point and of its separatrix in the corona, can be interpreted in terms of the magnetic breakout.