First observation of β Pictoris b with the narrow off-axis mode of GRA4MAT. Top left: superposition of the exoplanet fringes and host star fringes leaking through the MATISSE pinhole. The six exoplanet fringe peaks are vertically aligned at zero group delay. The six host star fringe peaks are at various group delay offsets, depending on the observation geometry. Top right: 2D power spectral density of the fringes shown in top left panel. The central peak represents the total photometry. The six vertically aligned peaks correspond to the planet fringes at zero group delay. The other six peaks correspond to the star at non-zero group delay. Bottom: preliminary β Pictoris b spectrum (blue), compared to a model Drift-Phenix model (black) and other adaptive optics and interferometric measurements.