In 1998 she founded the humanitarian organization Geneva Call which set out to involve armed non-State actors in banning the use of landmines.
[3][5] In 1997, Reusse-Decrey was a member of the Swiss delegation sent to Ottawa in 1997 to sign the United Nations Anti-Personnel Mine Ban Convention.
[6] Believing that the treaty should be supplemented by the possibility of negotiating with armed non-State actors, in 1998 she founded the NGO Geneva Call.
She is also a board member of the French organization Leaders pour la Paix and of Terre des hommes in Switzerland.
[2] In 2007, Reusse-Decrey married the American-born Daniel Warner, director of the CIG (Centre pour la gouvernance internationale) at the Graduate Institute of International and Development Studies in Geneva.