* High rates of absenteeism in some cities, says report
* Streamlining government is political challenge to Hollande
By Alexandria Sage
PARIS, March 6 (Reuters) - French public sector workers take an average of nearly a month off beyond annual leave, according to a report that highlighted problems facing President Francois Hollande as he seeks to streamline public offices and bring down France's deficit.
French public spending is among the highest in the world and due to hit 57 percent of national output this year. State workers make up one fifth of France's total employed ranks and their salaries account for a quarter of public expenditure.
A report by civil society think tank iFRAP found that local public workers in cities of over 100,000 residents, excluding Paris, missed nearly a month of work on average per year on top of holidays - over double the rate in the private sector.
The study calculated public servants in 25 cities missed work an average of 26 days per year, or 12 percent of total work days. That figure included temporary or long-term illness, work accidents, maternity and paternity leave and unexplained absences.
The highest figures were in the southern city of Montpellier, with an average 39 days of absence, followed by Grenoble and Strasbourg in the east, at 35 and 32 days each.
By contrast, the average equivalent absentee rate at five major companies surveyed by iFRAP - Air Liquide, BNP Paribas, Renault, Bouygues and ADP - was just 4 percent.
A November 2013 report by the auditing office of Languedoc-Roussillon department called Montpellier's absenteeism rate "a major worry" and recommended an action plan.
French employers frequently complain doctors are too ready to issue sick notes. French absenteeism rates are higher than the European average, International Labour Organization data show.
Some 3.7 million public and private sector employees in France worked "no hours" in 2012 during one week studied by the ILO versus 4.5 million in Germany, but above the 3.1 million UK employees, 1.9 million in Italy, and 557,000 in Switzerland.
The CGT public servants' union said the iFRAP data were misleading and did not take into account job functions, the age of workers and varying working environments.
"It's very hard to extract real figures that are representative," said the CGT's Philippe Vorkaufer.
Hollande has promised to find over 50 billion euros in public spending cuts between 2015-2017 to cut taxes and honour a deficit-cutting pledge by the euro zone's second-largest economy to its EU partners. The EU Commission on Wednesday told France it would miss its targets unless it took action.
Details on where the savings will come from will only be disclosed following local French elections late this month. The ruling Socialist majority is hoping to avoid a backlash from record high unemployment and a stagnant economy that have sent Hollande's approval ratings plummeting.
But while Hollande's "responsibility pact" unveiled in January seeks to lower businesses' costs by reducing their social charges, the government has thus far steered clear of radically slashing some 5.4 million state sector jobs, instead relying on attrition to reduce headcount numbers.
Cutting public servants would represent a politically risky move certain to mobilize powerful unions to the streets. It would also further exacerbate the welfare tab by pushing more people into unemployment.
"Any policy of lowering public spending must depend on the two principle spending items: social charges and personnel expenses," wrote a February study from the liberal Institut Montaigne think tank.
critics say Hollande's budgetary reform is confused, pointing to his reversal of a key measure begun by predecessor Nicolas Sarkozy designed to curb absenteeism by withholding pay for the first sick day taken. The fix spurred a 43 percent drop in one-day absenteeism rates in 2012, according to insurer Sofaxis, before its reversal in January. (Editing by Mark John)