She married an Italian aristocrat and became the founder and director of the literary journals Commerce (fr) (in France) and Botteghe Oscure (in Italy).

In Paris, the Caetanis frequented the artistic and literary world and were friends with Paul Valéry, Saint-John Perse, Valery Larbaud, Leon-Paul Fargue, and Adrienne Monnier.

With articles in three languages (French, Italian and English), Commerce published poets and writers already famous (such as James Joyce), but also younger artists, allowing them to make their works known.

After the Second World War, and the death of her son Camillo in December 1940, the family settled in the Roman residence of Palazzo Mattei Caetani in Via delle Botteghe Oscure [it].

In 1948, Marguerite Caetani founded a new journal, Botteghe Oscure, partly similar to Commerce, but now in five languages: English, French, Italian, German and Spanish.