"We are alongside our player, in the search for the truth," Villas-Boas told reporters on Tuesday.
We are sure that Alvaro is not racist. Olympique de Marseille represents multiculturality.
"He (Neymar) suffered, too. He knows precisely the impact of false accusations (after a rape case against him was dismissed and the perpetrators charged with perverting the course of justice).
"It's not correct towards Alvaro. It's a sensitive subject. Marseille and PSG are here to help find the truth."
Neymar struck Alvaro on the back of the head during the game and later tweeted saying he regretted not hitting the Spaniard in the face.
The Brazilian admitted on Instagram that it was a mistake to attack Alvaro but defended his own stance against racism.
Alvaro's team mate Valentin Rongier said: "I heard absolutely nothing. (Alvaro) is always smiling and respectful, even if he likes to make fun of others. Maybe he managed to make Neymar go berserk."