AFP - The Czech Republic's top court opened a hearing Tuesday to assess the compliance of the European Union's Lisbon treaty with the country's constitution following a complaint filed by eurosceptic senators.

In the televised hearing -- one of the last hurdles the treaty must clear to take effect -- the constitutional court will deal with a complaint motivated by fears that the treaty will give too much power to Brussels.

The complaint echoes concerns voiced by eurosceptic Czech President Vaclav Klaus, the last EU leader holding out on signing the text that aims to streamline EU decision-making and must be ratified by all 27 member states to take effect.

Klaus has repeatedly said he would wait for the court verdict before he signs.

He also angered the EU when he asked for an opt-out from the treaty three weeks ago in what his critics took as another attempt to delay the ratification.

The opt-out, designed to make sure the treaty will not allow ethnic Germans forced out of former Czechoslovakia for alleged World War II collaboration with the Nazis to claim back their property, will be on the table for an EU Council meeting in Brussels on October 29-30.

The constitutional court may take longer to decide, though.

"My forecast is that the court will not decide in this matter (on Tuesday)," Prime Minister Jan Fischer said on Monday.

"I expect we will learn when the court will meet and pass its verdict, which will be an important signal for the EU Council meeting," he added.

The EU has been waiting in suspense for Klaus's signature, the last step in the Czech ratification process after local lawmakers approved the treaty earlier this year.

With the current impasse, European Commission chief Jose Manuel Barroso, who won a second five-year term last month, is unable to nominate a new commission, because it is unclear what legal basis he should use.

The mandate of the current commission -- the EU's executive body that draws up legislation impacting the lives of about half a billion Europeans and policing the application of EU laws -- expires at the end of the month.