The prosecutors’ office in Madrid said that, according to a sexual consent law passed last year, Rubiales could face a fine or a prison sentence of one to four years if found guilty. The new law eliminated the difference between “sexual harassment” and “sexual assault,” sanctioning any unconsented sexual act.
Not sure if relevant, but in recent years, several countries have proclaimed universal jurisdiction for certain crimes. Increasingly often, countries assert the right to prosecute their own citizens for abuse of children even when committed abroad, which has been deemed necessary to counter “sex tourism”.
Given that this is an accusation of sexual assault, I won’t be surprised if Spain claims jurisdiction for sexual abuse of/by its citizens anywhere in the world.