It skewered Paris for spending a colossal 16.6 million euros to kit out the Grand Palais exhibition hall for a one-day summit to launch the Mediterranean Union, a pet project of the right-wing French president.

But anger has focused on a claim, made by a left-wing deputy, that Sarkozy spent 245,572 euros on a state-of-the art shower complete with in-built sound system, fitted in his suite at the summit venue and never even used.

The quarter-million-euro shower allegation was widely picked up by French and English-language media, in a new embarrassment for Sarkozy's government as it battles a string of recent scandals.

"It would be scandalous if it were true, but it is false," said French Budget Minister Eric Woerth.

Detailed reading of the budget report lists the sum as the total cost of an office and suite for the French leader -- including the shower -- and bilateral meeting rooms for the 40 delegations present.

Deputy Rene Dosiere apparently misread a summary of the budget report on French website Mediapart, which first published it this week.

The French foreign ministry insisted Paris had stayed within the budget of 180 million euros allocated for its EU presidency, whose costs are spread between various ministries.

Ministry spokesman Bernard Valero said it spent less than Berlin during its 2007 stint at the EU helm, despite unplanned events linked to the financial crisis and the Russia-Georgia conflict.

But he admitted spending on the Mediterranean Union summit was "higher" than for the 500 other events held during the presidency, saying a lack of suitable venues had forced officials to equip the Grand Palais from scratch.

Sarkozy's shower aside, the summit shopping list included 194,900 euros for potted plants, 653,703 euros for air conditioning and 301,208 euros for a conference podium while the end of summit dinner cost 1,010,256 euros -- more than 5,000 euros per head.

"For its scale, the irregular procedures followed and its massive impact on our public finances, the summit will go down as a record of sorts," the Cour des Comptes wrote in its report.

The Socialist opposition hit out at what they called "incredible, unbearable and unacceptable expenditure" as France battles to contain a spiralling public deficit.