Toward the end of World War II, the forces of Nazi Germany were retreating and near defeat.

At the request of two Swiss Orthodox Jews, Recha Sternbuch and her husband Yitzchak Sternbuch, and in coordination with them, Musy and his son Benoît Musy engaged in high-level negotiations with the Nazis to rescue large numbers of Jews in the concentration camps.

Following the Himmler–Musy Agreement [de] of 12 January 1945, Musy was involved in the release of 1,210 prisoners from the Theresienstadt concentration camp in February 1945.

The group was saved after $1.25 million was placed in Swiss banks by Jewish organizations working in Switzerland.

[2][3][4][5] Jean-Marie Musy's son Pierre received numerous equestrian competition titles and won the four-man bobsleigh gold medal at the 1936 Winter Olympics in Garmisch-Partenkirchen, Germany.