I think it was improvisation.

Moi aussi je voudrais bien le savoir. En plus le son qu'il y a au tout début est incroyable. Une atmosphère étrange.

Il s'agit d'une improvisation réalisée expressément pour la vidéo de présentation sans doute. Reste à savoir qui de Thomas ou de Baptiste l'exécuta... Mystère !

nice gay boys by the way.

@@musicisitall You think that since men who aren't American do not speak the same language as you are gay?

Actually I got curious and did some digging with Google, and I understated the case: there are actually THREE 32' reeds, with a ContreBasson on the Récit Expressif, so there are two manuals with 32' stops, and three such ranks on the Pedal. It's just as well the scale of the building is a match for such long-period waveforms! Here's what the builder's website had to say about the specification: The new organ has five manual divisions of 61 notes and a Pedal of 32 notes. The Specification is exceptionally rich. The Positif has 18 stops, the Grand-Orgue 16 stops, the Récit Expressif 17 stops, the Grand-Choeur 19 stops, the Solo 11 stops and the Pedal 20 stops, altogether 101 stops, 147 ranks and 8,000 pipes. Amongst the uncommon features of this organ, the following are particularly noticeable: A grand Plein-Jeu based on the Montre 32' on the Grand-Orgue; the harmonic series up to the ninth in 32' on the Pédale (Théorbe: 4 4/7' + 3 5/9') , in 16' on the Grand-Choeur and in 8' on the Solo (Harmoniques: 1 1/3' + 1 1/7' + 8/9'), and up to the seventh in 8' on the Positif; A Plein-Jeu Harmonique 2-8 rank on the Grand-Choeur; A battery of hooded Tubas on the Grand-Choeur; A reed battery based on the 32' Contrebasson on the Récit Expressif; Five ranks of chamade reeds on the solo winded on 6 (!) different wind pressures increasing from bass to treble. Amongst the exceptional colours, the series of harmonic flutes (8', 4', 2 2/3', 2', 1 3/5', 1') on the Solo must be noted; this was introduced by Jean Guillou in the organs of "Chant dóiseau" in Bruxelles and of the Tonhalle in Zürich. Jean Guillou also had the idea to add a Sesquialtera to the Grand-Orgue in order to allow more soloistic possibilities to this manual. The Contre-Bombarde 32' was not specified in the original contract but the Van den Heuvel brothers thought that the existing Contre-Trombone 32' (with its wooden resonators of relatively small scale) was not assertive enough for such a large instrument; so they gave this new stop to the City of Paris. Thus the organ of the Saint Eustache seems to be the only one in the world which has three independent 32' reed stops. To which I can only add: Bravo! Excellence before profit ! ! ! Muchos kudos to the builders. PS: I guessed wrong, at least partly, in my unresearched post: the "presumably open metal" 32' Principale basse in the Pedal division turns out to be "wood & metal". I don't know if it's open, closed or a mixture. The builders' excellent website gives much more on this formidable instrument, at vandenheuvel-orgelbouw.nl/

from Wikipedia: With 8,000 pipes, the organ is the largest pipe organ in France, surpassing the organs of Saint Sulpice and Notre Dame de Paris. The organ originally constructed by P.-A. Ducroquet was powerful enough for the premiere of Hector Berlioz's titanic Te Deum to be performed at St-Eustache in 1855. It was later modified under the direction of Joseph Bonnet. The present organ of St. Eustache was designed by Jean-Louis Coignet under the direction of Titular Organist Jean Guillou and dates from 1989 when it was almost entirely rebuilt by Dutch firm Van Den Heuvel, retaining a few ranks of pipes from the former organ and the wooden case, which is original. I don't know when the original organ was built. The church started construction in 1532. Construction took 105 years (!) The church was ransacked in the 1789 revolution. It was closed to Catholic worship in 1793 and used for a time as a barn(!); it was re-opened in 1795 with significant damage. The building was further damaged by a fire in 1844. Architect Victor Baltard directed a complete restoration of the building from 1846-1854, including the construction of the organ case, pulpit, and high altar and the repair of the church's paintings. The church was set afire during the rule of the Paris Commune in 1871, necessitating repairs to the attic, buttresses, and south facade. Living as I do in a place where a cathedral damaged in an earthquake, which includes a magnificent instrument, has been left to take its chances with the weather, I have to admire the dogged persistence of the "fidèles" in Paris. I do hope the Notre-Dame de Paris is soon put to rights in the same spirit.