We present O CAESAR, the Optical CAtalogue of Extragalactic SupernovA Remnants. O CAESAR will provide the largest homogenous optical survey of extragalactic SNR candidates taken by the same telescope (Canada-France-Hawaii Telescope, CFHT), the same instrument (SITELLE), and in similar observation parameters. SITELLE, the imaging Fourier transform spectrograph of the CFHT, offers a large field of view (11'x11'), complete spatial coverage, and a high spatial resolution (0.32" limited by the seeing), which are ideal to cover the whole disk of nearby galaxies. Using three filters, we are able to measure the strong emission lines [OII]λ3727, Hβ, [OIII]lλλ4959,5007, Hα, [NII]λλ6548,6583, and [SII]λλ6716,6731. The spectral resolution is variable and depends on the scientific goal. Our sample is volume limited (D ≤10 Mpc) and will include the galaxies of SIGNALS survey (∼40 galaxies) in addition to other galaxies that will be proposed specifically for our project to include different ranges of types, masses, and metallicities. Identification of the SNR candidates will be done automatically and will be based on the emission line criterium [SII]/Hα ≥ 0.4. The shock- excited nature of SNR candidates will be confirmed using the whole set of emission lines available with our SITELLE data.