Recent high-energy missions have allowed keeping watch over blazars in
flaring states, which provide deep insights into the engine powered by supermassive
black holes. However, having a quasar caught in a very bright flaring state is not easy
requiring long surveys. Therefore, the observation of such flaring events represents a
goldmine for theoretical studies.
Such a flaring event was captured by the INTEGRAL mission in June 2015 while
performing its (as of today) deepest extragalactic survey when it caught the prominent
blazar 3C 279 in its brightest flare ever recorded at gamma-ray energies. The flare
was simultaneously recorded by the Fermi gamma-ray mission, by the Swift mission, by the
INTEGRAL mission and by observations ranging from UV, through optical to the
near-IR bands. The derived snapshot of this broad spectral energy distribution of
the flare has been modeled in the context of a one-zone radiation transfer leptonic
and lepto-hadronic models constraining the single emission components. The derived
parameters of both models challenge the physical conditions in the jet. However,
very recently published very-high-energy (VHE) data at TeV energies are very close to our
lepto-hadronic model.