Florange 1991, luminous triangle with humming sound

Summary

In March 1991, a driver in the Moselle region of France noticed three lights arranged in a triangle in the sky. The sighting was accompanied by a steady humming sound, an unusual auditory detail for this type of report. No other witnesses came forward, and no additional information was available to corroborate or expand on the account. GEIPAN classified the case as C, meaning no conventional explanation could be determined.