If the nationwide referendum on the E.U. constitutional charter were held now, French voters would reject it by a narrow margin, according to a poll published Friday in the daily Le Parisien. According to the survey, which was carried out March 16 and 17 by the CSA research institute, 51 of those responding said they would vote to reject the charter, against 49 per cent who would vote yes. The French referendum will be held May 29. The CSA poll is the first in which opponents of the charter have the upper hand. A similar CSA poll taken February 23 and 24 showed 63 per cent in favour of the E.U. constitution, a 14-point turnaround in three weeks. Most observers believe that the reason for the sudden change of opinion is the discussion over the so-called Bolkestein directive, the E.U.'s proposal to liberalize services throughout the Union. The plan is opposed by every political faction in France and all the trade unions. E.U. Commission President Jose Manuel Durao Barroso has recently said he would push passage of the directive, which allows businesses in E.U. member nations to sell their services in other E.U. countries while complying only with the requirements of the country of origin. If adopted, the Bolkestein directive would forbid nations in which the services are sold from imposing any restrictions or controls, such as local collective bargaining agreements or environmental and consumer protection standards. French politicians and trade unions say the directive would lead to "social dumping" and a loss of jobs.