Concerning the organ it was in 1927, Raugel gives the following specification:
| Grand-Orgue | Positif | Récit expressif |
| 16 Montre | 16 Quintaton | 8 Bourdon |
| 16 Bourdon | 8 Flûte Harmonique | 8 Flûte Traversière |
| 8 Montre | 8 Salicional | 8 Voile de gambe |
| 8 Bourdon | 8 Unda Maris | 8 Voix Céleste |
| 8 Flûte Harmonique | 4 Prestant | 4 Flûte Octaviante |
| 8 Gambe | 4 Flûte Octaviante | 2 Octavin |
| 4 Prestant | 2 Doublette | 6 Trompette |
| 2⅔ Quinte | 1 Piccolo | 8 Basson-Hautbois |
| V Cornet | II–V Cornet | 8 Voix Humaine |
| III–VI Plein Jeu | 16 Basson | 4 Clairon |
| 16 Bombarde | 8 Clarinette | |
| 8 Trompette | 8 Trompette | |
| 4 Clairon |
According to other authors there was a Flûte Octaviante 4 on the Grand-Orgue; I think this quite likely; there are often such discrepancies between various sources.
In 1934, on Olivier Messiaen’s request, seven new stops were added to the organ as well as a Barker lever for the Positif. (Messiaen told me the Récit/Positif was quite unplayable before this addition!)
| Grand-Orgue | Positif | Récit expressif |
| 16 Montre | 16 Quintation | 16 Bourdon |
| 16 Bourdon | 8 Principal | 8 Gambe |
| 8 Montre | 8 Salicional | 8 Voix Céleste |
| 8 Gambe | 8 Unda Maris | 8 Flûte |
| 8 Flûte harmonique | 8 Flûte Harmonique | 4 Flûte |
| 8 Bourdon | 8 Cor de Nuit | 2⅔ Nasard |
| 4 Prestant | 4 Prestant | 2 Octavin |
| 4 Flûte | 4 Flûte | III Cymbale |
| 2⅔ Quinte | 2⅔ Nasard | 8 Trompette |
| III–VI Plein Jeu | 2 Doublette | 4 Clairon |
| V Cornet | 1⅜ Tierce | 8 Basson-Hautbois |
| 16 Bombarde | 1 Piccolo | |
| 8 Trompette | II–V Cornet | 8 Voix Humaine Tremolo |
| 4 Clairon | 16 Basson | |
| 8 Trompette | ||
| 8 Clarinette |
Pédale
32 Bourdon
16 Contrebasse
16 Soubasse
8 Violoncelle
8 Flûte
8 Bourdon
4 Octave
16 Bombarde
8 Trompette
4 Clairon
From 1962 to 1965 both stop and note actions were electrified by Beuchet-Debierre and eight new stops were added to the organ together with a new Positif box to enclose seven Positif stops, a new console and a combination system:
Pédale
32 Soubasse
16 Contrebasse
16 Soubasse
8 Flûte
8 Bourdon
4 Flûte
IV Plein Jeu
16 Bombarde
8 Trompette
4 Clairon
+ Tremolo du Récit
After the extensive cleaning and renovation of the church’s interior, the organ is being cleaned and overhauled (there were many leaks in the wind-trunks). Olivier Messiaen would have liked two new mutations on the Récit: a Septième 11/7 and a Neuvième 8/9, a 32’ Bombarde on the Pédale and an 8’ Trompette en Chamade (not overwhelming, he said). At the present time I do not know whether these additions will be done or not; I should be inclined to keep the organ exactly as Messiaen played it.