Musnad Ahmad 25:1614

'Abd al-Razzaq narrated to us, Ibn Jurayj informed us, he said: 'Abd al-Karim and others informed me, from Miqsam, the freed slave of 'Abdullah ibn al-Harith, that Ibn 'Abbas informed him: That the Prophet, peace and blessings of Allah be upon him, "set the penalty for a menstruating woman [if one has intercourse with her] at one dinar. If he has intercourse with her after the blood has ceased, but she has not yet performed ghusl, then [the penalty is] half a dinar." All of that is from the Prophet, peace and blessings of Allah be upon him.