Kautilya's Arthashastra 3.3.31

3.3.31

ta evāgamyayor ardhadaṇḍāḥ, tathā pratiṣiddhapuruṣavyavahāreṣu ca // iti pratiṣedhaḥ /

With regard to a man and a woman who, though forbidden to carry on any mutual transaction, help each other, the woman shall be fined 12, 24 and 54 panas respectively according as the help consists of (i) small things, of (ii) heavy things and (iii) of gold or gold-coin (hiranyasuvarnayoh); and the man, at double the above rates. With regard to similar transaction between a man and a woman who cannot mix with each other (agamvayoh), half of the above punishment shall be levied. Similar punishment shall be meted out for any forbidden transaction with any men. Thus forbidden transactions are dealt with.