Germany and France have pledged to start harmonising their taxes as an example to Europe of how to avoid future crises, while ruling out joint euro zone bonds or topping up the current crisis fund. German Chancellor Angela Merkel and French President Nicolas Sarkozy said after a brief summit in Freiburg on the German border with France that they both must set examples for the currency zone. 'We have agreed to the convergence of German and French tax policies and I thank the German chancellor for this opening. It is very important to be able to say to our partners, we are in the euro zone, we must converge to defend the euro,' Sarkozy told a joint news conference with Merkel. 'We should set an example on questions of competitiveness, how far we can go beyond pure budget policy,' said Merkel. The leaders of the two euro zone giants both rejected a proposal for joint euro zone bonds, championed by Luxembourg's prime minister Jean-Claude Juncker with Italian support. Juncker, chairman of the group of euro zone finance ministers, floated the idea of creating a euro debt instrument as a way of deterring market speculation. Germany has energetically attacked the idea, which would tie the borrowing costs of major European economies to peripheral members such as Greece, Ireland and Portugal. This would push up borrowing costs for countries like Germany and France.