Sighting in Argenteuil, July 13, 1979

At around 11:30 pm, two witnesses were on a seventh-floor balcony when they saw a red-orange ball in the sky coming from the northwest and heading toward central Paris. The object seemed to come to a stop above La Défense-Nanterre, then suddenly went out. This first phase lasted about thirty seconds.

Three minutes later, at the spot where the first object had vanished, the witnesses saw a flat, bright white shape. It moved about in the sky, then disappeared very quickly on an upward path. The witnesses were stunned. No other testimony was collected.

The investigation considered a double misidentification: first an aircraft (red color, initial speed comparable to a plane's), then a fireball (whiteness, strong brightness, climb toward the zenith). Some oddities remained, however: the stop followed by the extinction would imply a helicopter and a cloud, and since the second phase began in the same place, a fireball would be a coincidence. The description was ambiguous and could also fit a light fading away, with no real angular movement. No bright star lay in the direction of Nanterre.

Key data were missing: the duration of the second phase, angular height, azimuths, angular dimensions, and a separate statement from the second witness. The gendarmes carried out no investigation. Hypotheses existed, but the uncertainty was too great, so the case was classed C: unusable for lack of reliable information.