It was narrated from Ibn 'Abbas from the Prophet (ﷺ) concerning a man who has had intercourse while she was menstruating:
"Let him give a Dinar or half a Dinar in charity." (RU)
English reference (RU): Vol. 1, Book 1, Hadith 290 (RU)
Arabic reference (RU): Book 1, Hadith 291 (RU)