European leaders on Friday signed a new treaty to reinforce budgetary discipline in the wake of the debt crisis.

A German demand as the price of financial solidarity, it will introduce "golden rules" making balanced budgets mandatory.

Here are the main points:

- The 'golden rule'

Countries that sign up commit to balanced budgets, ideally in surplus over the course of economic cycles. The structural deficit, which strips out one-off effects such as debt repayments and the economic cycle, should be capped at 0.5 percent of gross domestic product. Countries with debts comfortably below the 60-percent-of-GDP EU threshold will get more leeway, up to 1.0 percent of GDP for the structural deficit.

- Automatic correction

Each state must ensure that "automatic consequences," or brakes, are triggered when this goal is missed by too great a margin, and are obliged to take action within a certain timeframe.

- Rule enshrined, if possible, in constitutions

The treaty asks states to insert the new rule "preferably" into their constitution. This is not an obligation; other legal guarantees that the rules will be respected will also be accepted. Germany had to back down on its demand for a constitutional requirement after numerous countries refused, saying changing their constitutions may require referendums.

- Court supervision

The European Court of Justice will verify that countries adopting the treaty have delivered on their legal commitments at national level and under set criteria. Where this is not the case, a state could be taken to the court by peers and, in the ultimate sanction, face an EU fine amounting to 0.1 percent of GDP.

Germany wanted to go further in giving the court powers to penalise broken budget commitments. France would not give up its sovereignty here, so Germany backed down, for now. If significantly enhanced eurozone governance rules become integrated, the court could monitor national budget planning and other policies, Chancellor Angela Merkel has said in an interview.

- Near-automatic sanctions for excessive deficits

The annual public deficit limit will remain at 3.0-percent of GDP, as enshrined in a longstanding European Union Stability and Growth Pact (SGP). If the executive European Commission deems a state to have violated this ceiling, there is a risk of financial penalties. Imposition of these sanctions will be harder to wriggle out of than at present with a qualified majority of states needed to stop the fine. Such a vote is difficult to obtain.

Germany, the Netherlands and the Commission would like to go further by applying this principle to public debt as well. Italy, which has high national debts, rejected this push.

- Eurozone summits

At least two summits per year are envisaged purely for eurozone states, with non-euro pact signatories invited "at least" once per year. Poland, which aims to adopt the euro around 2015, wants guarantees it can participate in all meetings at which decisions could affect it. France refuses to open all of these summits to non-euro states.

- The treaty's entry into force

The inter-governmental treaty is to be signed by 25 of the 27 EU states -- the 17 eurozone states and nine others. Britain and the Czech Republic refused to take part. It will enter into force once 12 states have ratified the treaty.