Superfluorescence (SF) refers to a well-known phenomenon in atomic physics in which emitters can synchronously emit photons through their long-range interaction, resulting in accelerated and bright coherent emission. The SF process should be theoretically efficient by combining similar emitters with large dipole moment within a superlattice, but experimentally strong limitations arise from their organization within an assembly, due to the difficulties of obtaining spectrally identical individual emitters with high densities and identical dipole orientations. The control of the inter-emitter distance is also a key parameter, with a trade-off between the necessary electromagnetic coupling and the detrimental electronic coupling. That is why in solid-state physics, SF has been demonstrated in very limited systems. Recently, perovskite nanocrystal (pNC) superlattices have joined this shortlist, thanks to their optimal optical and structural properties. Nevertheless, a critical frontier remains unexplored: the demonstration of cavity-enhanced SF of pNC superlattices coupled to a photonic structure. To tackle this challenge, CSUPER2 aims to integrate pNC superlattices into an open fibered-microcavity specially designed for solution-processed individual nanoemitters. This integration would advance the field of cooperative light-matter interactions in pNCs by unlocking cavity-enhanced SF, which is expected to exhibit higher brightness at lower excitation fluences, improved coherence properties, and even SF lasing effects. Overall, CSUPER2 aims to achieve 3 main objectives: (1) to synthesize cubic-shaped pNCs with narrow size-distribution through soft chemistry and ligand-engineering in order to assemble the pNCs into controlled long-range ordered superlattices; (2) to demonstrate SF in the resulting pNC superlattices and investigate in detail the SF fundamental optical properties, such as the spectral signatures, the ultrafast dynamics, the coherence and the photon statistics, using steady-state and time-resolved spectroscopy as well as quantum optics experiments at room and low temperature. The effect of disorder will be precisely analysed in order to assess the number of coherently coupled pNCs contributing to the SF signal; (3) to investigate unexplored areas of cavity-enhanced SF from pNC superlattices, by using a tunable fibered microcavity in order to modify and tune the key element responsible for SF emission, i.e. the dipole-dipole coupling mediated by the vacuum fluctuation of the electromagnetic field. The cavity will thus constitute a new knob to explore the rich physics of SF, and ultimately explore the transition from conventional to SF lasing. To fully exploit the experimental results, the CSUPER2 project will benefit from a strong theoretical support on collective light matter effect. The theoretical studies of the collective emission properties in pNCs superlattices will be done by considering precisely the effect of disorder, along with the effect of the cavity coupling.