Here's what Skinner & Verhoeven say about the display:

Alekhine ended his self-imposed exile from the chess-playing arena on Sunday, 1 February, when he gave another of his sensational blindfold exhibitions and set up a new world record for simultaneous blindfold display. The display took place in the great hall of the Petit Parisien, and was organised jointly by the newspaper Excelsior and the Federation des Echecs. He was able to improve on the world record established by him in New York last April, when he played 26 games, winning 16, drawing five and losing five. On this occasion he played against 28 opponents and scored 22 wins, three draws and three losses. Opinions differ as to the relative strength of the opposition on the two occasions. Alekhine writing in On the Road to the World Championship was in no doubt that the opposition in New York was stronger, but the report in La Strategie 1925, p24-5, expressed the opposite view, giving as its reason that Alekhine had permitted most of the boards in the Paris exhibition to be taken by teams of players.

The seance was opened at 10.10 am by M. Fernand Gavarry, President of the F.F.E. who introduced Alekhine to the players. Using a system similar to the one he employed in New York, Alekhine announced that he was dividing the players into six groups. On the first seven boards he played 1.e4, on the next six 1.d4 and on the 14th board 1.f4. The same pattern was repeated for the last 14 boards. Play began at 10.18 am.

He has what is probably the most marvelous chess memory that ever existed. It is said that he knows by heart every game played played in any tournament by either a first class club player or a master during the last twenty-five or thirty years. He certainly knows by heart all of the games ever played by any of the first-class masters.

In so-called simultaneous blindfold performances Alekhine has no equal among the masters, past or present. Not long ago, in Paris, he played thirty boards simultaneously without sight of men or boards; a truly prodigious feat.

Few masters, now or in the past, have devoted much time or energy to this kind of exhibition work. Some have thought that it would be injurious, which no doubt it would be if carried too far; others, like the writer, have thought that there was not sufficient compensation to justify the enormous amount of labor involved in such exhibitions.

There is a great deal of misunderstanding with regard to blindfold playing. The question is often asked, "How many games blindfolded can you play at once?" "Do you make a practice of it?"

As a matter of fact, almost any first-class master would be able to play six simultaneous blindfold games without preparation. However, to come near Alekhine's figure is quite different, and to imitate him in that respect is quite impossible. It would require his prodigious memory combined with his enormous capacity for mental work in connection with chess.

Reti in 1928 and Koltanowski in 1931 succeeded in edging up the record to 29 and 30 boards respectively. Alekhine reclaimed the record on July 16 1933 at the World Fair in Chicago when he took on 32 opponents.

In a subsequent interview with Chess Review, Alekhine said, "I found less difficulty in playing 32 games than I had anticipated, considering that it was my first performance on such a scale in six years. But I would have no fear in tackling 35 and possibly up to 40. I can carry that many games in my mind, but every additional game means more time, and the element of fatigue enters. It might be an idea to devote two days to such an exhibition. I would of course agree not to look at a chess board at any time until the performance was over. Under those conditions, I am confident I could carry on 40 games blindfold, and would not set the limit even there."