The Mexican Supreme Court of Justice [official website] on Thursday ruled [press release, in Spanish] that Wal-Mart de Mexico [corporate website; JURIST news archive] may not pay employees in part with vouchers redeemable only at its stores. The court nullified the employment contract of a worker who challenged the voucher payments, finding that they violated Article 123 of the Mexican Constitution [PDF text], which guarantees the right to “dignified and socially useful work.” The court likened the arrangement, which Wal-Mart called the Plan of Social Welfare, to a practice that prevailed during the dictatorship of Porfirio Diaz [profile], who ruled Mexico [JURIST news archive] in the late 19th and early 20th centuries. Until the practice was abolished by the current constitution in 1917, workers could be forced to buy exorbitantly priced goods at company stores. AFP has more. AP has additional coverage. From Mexico City, El Universal has local coverage.