Sighting in Saint-Mandrier-sur-Mer, May 23, 2019

The witness was aboard their boat, about 5 nautical miles (roughly 9.3 km) offshore, south of Cap-Cepet, when at 07:30 they saw a black ball appear in the west, 15° above the horizon. It seemed to be flying at about the altitude of an airliner, but faster. Halfway along its path it turned a very bright "chrome" appearance, accelerated sharply (its speed roughly tripled) and climbed toward the southeast. The witness lost sight of it in the south, at 45° elevation. The sighting lasted 5 to 7 seconds, with no noise, halo, trail, smoke or sparks.

The GEIPAN rated the consistency of the account as medium: there was only one witness, no photos or video, and some data were incomplete, notably the object's apparent size and the angular distance it covered.

The hypothesis retained was a novelty balloon. Black and chrome match the two possible finishes of such balloons (painted or aluminized Mylar®), and their round shape, lit by the Sun on the east side, gives a shiny look. The object's initial west-to-east motion matched the wind above 750 m exactly; that wind curves widely over the sea and may have come from the coast near Marseille, Martigues or Port-Saint-Louis-du-Rhône. With very good weather, the balloon could have been released or lost from a beach or creek along the coast.

The strangeness the witness perceived is explained as follows: the colour change comes from a two-tone balloon with a dark side and a shiny side, whose perspective or rotation may have changed its look. Without reference points, speed, distance and size are hard to judge; the object was probably smaller and lower than assumed, which makes its apparent speed seem too high. The change in direction and speed may result from climbing into an area of stronger winds blowing toward the west-northwest. The imprecise angular size and distance prevent further checks. The GEIPAN classified the case as B: a very probable novelty balloon.