Hello Eleonora, this game is a popular game outside Italy as well, though I've heard it called "witchy" when I was a child. I don't know what it's called now. 

Il gioco italiano Strega comanda colore - The italian game The witch dictates the color

All the children in Italy know the play game “Witch dictates the color”. The rules of the game: Every children in turn acts the part of the witch. The other children ask her: “Witch dictates the color, what color do you want?” The witch chooses a color and says it loudly [or shouts it out aloud] (for example: Yellow!). All the children run away/around and look for something yellow before the witch catches them. If the witch catches a children before he/she/they ["they" can be gender neutral instead of plural] touches something yellow, this children will become the new witch and the game restarts.