Kautilya's Arthashastra 4.2.28

4.2.28

anujñātakrayād upari caiṣāṃ svadeśīyānāṃ paṇyānāṃ pañcakaṃ śatam ājīvaṃ sthāpayet, paradeśīyānāṃ daśakam //

The Superintendent of Commerce shall fix a profit of five per cent over and above the fixed price of local commodities, and ten per cent on foreign produce. Merchants who enchance the price or realise profit even to the extent of half a pana more than the above in the sale or purchase of commodities shall be punished with a fine of from five panas in case of realising 100 panas up to 200 panas.