Date:
July 3, 1997
Location: Perigny, France
In
the night of July 3, 1997 at 4 a.m., a witness in his
sailing ship observes an intense gleam which goes down
quickly during 2 to 3 seconds, stabilizes itself a few
moments before moving out again very quickly horizontally
to disappear in 2 or 3 seconds approximately. The witness
calls his two fellow-members who were sleeping to announce
his observation to them when they are witnesses to a second
phenomenon in the form of yellow rhombus ochre with lights
on the tops.

Witness drawing of the object.
Source:
GEIPAN (French government UFO program)
The
following is a brief summary of the case. The case is
from the files of the official French government UFO research
program GEIPAN (Group for the Study and Information of
Unidentified Aerospace Phenomenon), which is a part of
CNES, the French government space agency. The full report
and file on this case [in French language] is on the GEIPAN
website at http://www.cnes-geipan.fr/geipan. The case
has been classified as a 'Class D' case, which are the
unexplained cases in the GEIPAN files.
The
summary has been translated using automatic computer translation,
so it is not a perfect translation.
In
the night of July 3, 1997 at 4 a.m., a witness in his
sailing ship observes an intense gleam which goes down
quickly during 2 to 3 seconds, stabilizes itself a few
moments before moving out again very quickly horizontally
to disappear into 2 or 3 seconds approximately. The witness
calls his two fellow members who were sleeping to announce
his observation to them when they are witness to a second
phenomenon in the form of yellow rhombus ochre with lights
on the top. The object moved very quickly at the level
of the clouds and disappeared at the end of 10 to 15 seconds.
The phenomena observed were not explained.
Source:
http://www.ufoevidence.org/cases/case1122.htm