In 1935, Olgiati became the secretary of the pacifist organization Service Civil International (SCI), created in 1920 by Pierre Cérésole.
It was a platform of non-governmental organizations, led by SCI, and developed since 1937 a humanitarian mission to support children mainly in the Republican zone.
After the end of the war in January and February 1939, the Swiss Aid continued providing services to the refugee population in the south of France, where they reorganized the infrastructures.
The Swiss colony for Spanish refugee children Château lleva Lac in Sigean (Aude) and the Elna's maternity, run by Ruth von Wild and Elisabeth Eidenbenz, were created.
Olgiati remained in the secretariat, coordinating a campaign for humanitarian work in the "free zone" of southern France and in Switzerland from 1940 to 1941, the activities of the volunteers and the negotiations with the authorities in Bern.
Olgiato had founded the association as Swiss aid in extra-European regions (ASRE) (Schweizerisches Hilfswerk für aussereuropäische Gebiete, in German), together with Regina Kägi-Fuchsmann.