He was the champion of France three times: 1933, 1937 and 1938. During the 1930s he participated in several tournaments. He finished equal 2nd with Tartakower in Paris 1930. This was a strong tournament won by Znosko Borovsky and Lilientahl and Mieses were playing.
From 1934 to 1935 Gromer toured Spain playing blindfold games and giving simultaneous exhibitions. During this period he tied for first in the Madrid 1934 tournament and also defeated the strong Spanish players Sanz Aguado and Ortueta in matches.
At the end of 1935 George Koltanowski, then living in his birth country of Belgium, wrote an article in the magazine El Ajedrez Espanol in which he accused Gromer of running a scam against the small clubs that welcomed him. But Spanish newspaper chess columns of the time written by such respectable writers as Ramon Rey Ardid in the Barcelona paper and Manuel Golmayo in the Madrid paper never mentioned anything and their comments were always favorable to Gromer.
Koltanowski had criticized Gromer’s conduct in Spain earlier, but in the October 1935 issue of Chess magazine he stated he had some very unpleasant things to say about Gromer and it was his hope that the object of his attack actually read them. Koltanowski, claiming he was publishing the article ot the request of the San Sebastian Chess Club, accused Gromer of victimizing Spanish players and doing the game a lot of harm and by publishing the article he hoped to stop people from being duped.
The article sounds preposterous and nobody knows if any of it is true or not especially since it's known that Koltanowski sometimes had problems with facts and he was known to embellish his stories on occasion.
The charge was that Gromer would turn up in some small town, announce that he was broke and beg the chess club to arrange a simultaneous display for him. The display would be arranged and he would be paid his fee. He would then stay on and claim he had borrowed money from club members and he wanted to play one more simul so he could pay them back, but he only paid back half of what he owed. He would then request another simul so he could make enough money to pay the balance. By the time the club got through paying his fees so their members could get their money back the club was broke. Koltanowski claimed that in San Sebastian Gromer didn't pay back any of his debts and stayed at the finest hotels at the club's expense.
Gromer finished second in Paris 1938 and one notices that he was one of the players who participated in 1939 in the Buenos Aires Olympiads who decided to stay in Argentina when the war broke out in Europe. During that time many of the exiles eked out an existence by giving simultaneous exhibitions. While in Argentina he played he played matches and in 1940 he participated in the Torneo Mayor which allowed him to qualify for the title of champion of Argentina. He tied with Guimard and Sulik but was defeated by Guimard in the playoff. In 1941 he finished in the middle of the table in a tournament in Sao Pedro, Brazil.
Gromer first turned up in Strategy magazine in 1922 where it was reported that he finished second in a thematic King's Gambit tournament organized by a Paris club. It was also mentioned that Gromer was the nephew of the French player Jacques Grommer who had taught him how to play chess. He would have been 14 at the time.
On March 4, 1923 the Parisian newspapers reported that a simultaneous was given by Gromer, but reported his age as 13 (he was apparently small for his age) and claimed he was a gifted pupil who was about three years ahead in school. In fact, at the time of the simul he would have actually been 14 or 15, but in those days his exact birth date was unknown. It's also been reported that the same was true of Samuel Reshevsky. Some reports indicate that he was actually about three years older than his parents claimed when he was touring the country as a child prodigy. Like Reshevsky's parents, the press was manipulated to make a better story. Gromer's parents were Isaac Gromer and Ida Gordon. Both were born in Vilnius, Lithuania which at the time was called Vilna and was part of the Russian Empire. They were married in Berlin in 1906. Gromer's father was a mathematician and his mother the daughter of a Berlin rabbi.
More about that claim that he was the nephew of Jacques Grommer, a chess coach at the Cafe de la Régence: Jacques Grommer emigrated to the United States in January 1912 which means that Aristide would have had to have learned chess from his uncle at the age of about three and a half.
Also mysterious was his return to France from Buenos Aires which it seems he did in May of 1942 just as the Nazi persecution of Jews in France intensified. In May of 1942 the Germans insisted on Jews wearing the Star of David and there was a big roundup of Jews in July of 1942, so it's unknown how Gromer managed to survive in France during World War Two. After the war he only turns up in 1947 when in February he lost a match to Tartakower, scoring two losses and four draws. He also played in the Paris and French championships. After that, almost nothing is known about him. It appears that Gromer died in 1966 at a psychiatric hospital in Plouguernevel, France.
Tactical possibilities abound in the following game played in the 1932 Olimpiad.