Marcel Dupré (1886-1971) was born in Rouen, studied at the Paris Conservatoire under Guilmant, Vierne and Widor, and later taught there as professor of organ performance and improvisation. He succeeded Widor as titular organist at St. Sulpice in 1934, and held that position until his death. This Souvenir was his last composition, written in 1969 in memory of Hélène Jon, a lifelong friend whose funeral he was unable to attend. The manuscript was given to Hélène's daughter Josette, and was not published until 25 years after the death of Dupré, as his Opus 65bis.
There is more about this piece in the excellent book about Marcel Dupré by Graham Steed on page 208 of the book here;
The whole book is available to read here.