The European Union's new fiscal treaty for tighter budget co-ordination has came into force. 25 EU countries signed the treaty in March to prevent the recurrence of credit woes triggered by the fiscal crisis in Greece. Britain and the Czech Republic opted out. The treaty came into effect in the eurozone after it was ratified by 12 of the 17 eurozone members, including Germany and France. The treaty obliges signatories to keep their fiscal deficits below 0.5 percent of GDP. They have to incorporate the rule into national legal systems, preferably in constitutions. Any member state that deviates from the balanced budget rule will be fined up to 0.1 percent of its GDP. EU leaders regard the treaty as the first step toward the group's fiscal integration.