  We used multi-wavelength high-resolution data from ARIES, THEMIS, and SDO
instruments, to analyze a non-standard, C3.3 class flare produced within the
active region NOAA 11589 on 2012 October 16. Magnetic flux emergence and
cancellation were continuously detected within the active region, the latter
leading to the formation of two filaments.
  Our aim is to identify the origins of the flare taking into account the
complex dynamics of its close surroundings.
  We analyzed the magnetic topology of the active region using a linear
force-free field extrapolation to derive its 3D magnetic configuration and the
location of quasi-separatrix layers (QSLs) which are preferential sites for
flaring activity. Because the active region's magnetic field was nonlinear
force-free, we completed a parametric study using different linear force-free
field extrapolations to demonstrate the robustness of the derived QSLs.
  The topological analysis shows that the active region presented a complex
magnetic configuration comprising several QSLs. The considered data set
suggests that an emerging flux episode played a key role for triggering the
flare. The emerging flux likely activated the complex system of QSLs leading to
multiple coronal magnetic reconnections within the QSLs. This scenario accounts
for the observed signatures: the two extended flare-ribbons developed at
locations matched by the photospheric footprints of the QSLs, and were
accompanied with flare loops that formed above the two filaments which played
no important role in the flare dynamics.
  This is a typical example of a complex flare that can a-priori show standard
flare signatures that are nevertheless impossible to interpret with any
standard model of eruptive or confined flare. We find that a topological
analysis however permitted to unveil the development of such complex sets of
flare signatures.
