  Bipolar planetary nebulae (PNe) are thought to result from binary star
interactions and, indeed, tens of binary central stars of PNe have been found,
in particular using photometric time-series that allow detecting post-common
envelope systems. Using photometry at the NTT in La Silla we have studied the
bright object close to the centre of PN M3-2 and found it to be an eclipsing
binary with an orbital period of 1.88 days. However, the components of the
binary appear to be two A or F stars, of almost equal masses, and are thus too
cold to be the source of ionisation of the nebula. Using deep images of the
central star obtained in good seeing, we confirm a previous result that the
central star is more likely a much fainter star, located 2 arcseconds away from
the bright star. The eclipsing binary is thus a chance alignment on top of the
planetary nebula. We also studied the nebular abundance and confirm it to be a
Type I PN.
