Their collaboration got well known immediately, and their compositions were recorded by major French singers such as Michel Polnareff, Christophe, Dalida, Petula Clark, Claude François and Mireille Mathieu.
1975 was the major breakthrough for both Paul de Senneville and Olivier Toussaint with the triumph of "Dolannes Melodie" which launched the trumpet player Jean-Claude Borelly.
"Ballade pour Adeline", composed by Paul de Senneville and Olivier Tousaint, was the first song recorded by Richard Clayderman at Delphine studio, and it sold over 22 million singles in 38 countries through the years 1977 to 1979.
In 1977 the synthesizer project By the Savers (Olivier Toussaint together with French musicians Roland Romanelli and Jean Baudlot) released one single Help Me across Europe which didn't chart anywhere.
In 1983, with the song "Eden is a magic world" (composed by Paul de Senneville), Olivier Toussaint got No.1 in the charts in France, Switzerland and Wallonia, the French speaking part of Belgium.
Besides producing and recording music for several international instrumentalists such as Richard Clayderman, Nicolas de Angelis, and Ocarina group, Delphine activities is in instrumental an advertising film and clip production.