Plato, Laws 917e

τυπτέσθω πληγὰς ὑπὸ κήρυκος ἐν τῇ ἀγορᾷ κηρύξαντος ὧν ἕνεκα μέλλει τύπτεσθαι. τὰ δὲ κιβδηλεύματά τε καὶ κακουργίας τῶν πωλούντων οἵ τε ἀγορανόμοι καὶ οἱ νομοφύλακες, πυθόμενοι τῶν ἐμπείρων περὶ ἕκαστα, ἀναγραψάντων ἅ τε χρὴ ποιεῖν τὸν πωλοῦντα καὶ ἃ μή, καὶ πρόσθε τοῦ ἀγορανομίου θέντων ἐν στήλῃ γράψαντες νόμους εἶναι τοῖς περὶ

after that the herald has first proclaimed the crimes for which the seller is to be beaten. Touching acts of fraud and wrongful acts done by sellers, the market-stewards and the Law-wardens, after making enquiry from experts in each trade, shall write out rules as to what the seller ought to do or avoid doing, and shall post them up on a pillar in front of the stewards office, to serve as written laws and clear instructors