French supermarket giants Carrefour and Casino traded further blows Monday over their operations in Brazil, a key market where both are claiming a tie-up with the same company. Casino is fighting to keep its alliance with longtime Brazilian partner, CBD Pao de Acucar which Carrefour has courted in a bid to build up its business. Casino said Monday it had lodged a second request for arbitration from the International Chamber of Commerce aimed at compelling the Diniz family -- CBD\'s main shareholder -- to respect a partnership agreement which was to give Casino majority control of the Brazilian group this year. Earlier on Monday, Carrefour\'s board approved its plan to partner with CBD. Initiated by investment fund Gama and financed in part by BNDES, the Brazilian development bank, this Carrefour tie-up would merge the French giant\'s Brazil interests with CBD into a new company that would in turn own 11 percent of Carrefour. The board deemed the project \"fully in line with Carrefour\'s strategy to strengthen its footprint in its principal growth markets and would create value\" for the company, a statement said. The board noted, however, that the \"transaction remains subject to certain conditions, including approval by CBD and final approval by BNDES’s board of directors.\" Carrefour said the deal would produce synergies worth between 600 and 800 million euros a year, with projected sales of 30 billion euros in 2011. Casino increased its longtime stake in CBD to 43.1 percent last week as it battles to head off the Carrefour arrangement. Press reports on Monday said BNDES is looking for consensus on the deal in an effort to defuse tensions between the parties. Other reports said Casino chief executive Jean-Charles Naouri was in Brazil and set to meet the BNDES chief later on Monday.