She is remembered as an effective member of Danske Kvinders Fredskæde, the Danish branch of the Women's International League for Peace and Freedom (WILPF), later known as Kvindernes Internationale Liga for Fred og Frihed (KILFF).
[1] Struck by the hostilities of the First World War, in 1916 Cederfeld de Simonsen joined the peace organization Danske Kvinders Fredskæde, becoming the head of its Funen chapter in 1919.
Together with Clara Tybjerg and Henriette Beenfeldt, Cederfeld de Simonsen maintained that it could only help if there were two organizations in Denmark striving for peace as they could extend there interests more widely.
[1] Cederfeld de Simonsen was particularly effective in increasing membership of the Funen chapter of the KILFF, making it by far the largest local organization with 4,000 members.
[1] Maintaining her interest in the peace movement for the rest of her life, Benny Cederfeld de Simonsen died in Copenhagen on 16 January 1952.