[3] After his experience with the Italian resistance movement during World War II, he continued his artistic career as leader of the "Pittura" Group and editor of art magazines such as Il 45 and Realismo, together with Raffaele De Grada.
[8] He held also many solo exhibitions in art galleries and museums in Paris,[9] Berlin,[10] Amsterdam,[11] Barcelona,[12] Stuttgart[13] and São Paulo.
[14] Treccani then developed the various features of his artistic research along parallel lines, continuing to work and exhibit in towns and cities in Italy and abroad, and alternating this “nomadic” activity with regular and creative stays in Macugnaga and Forte dei Marmi.
[22] In 2006 the town of Forte dei Marmi organized the exhibition Le mutazioni del realismo - Opere inedite 2003-06 at the Fortino.
[23] In 2009 another large retrospective exhibition of Treccani's work inaugurated the renovated rooms of Palazzo Barberini in Montichiari,[24] just a few months before his death.
In December 2009, during the 40th anniversary of the Piazza Fontana bombing, Treccani's painting Un popolo di volti was exhibited at the Royal Palace in Milan.
In March 2011, the same venue exhibited the painting Le cinque giornate di Milano on the occasion of the 150th anniversary of the unification of Italy.
Dalle poetiche del realismo alla poesia della realtà, Grafo Edizioni, Montichiari, 2009 Giorgio Seveso (a cura di), Le parole e la pittura.