Georgina Ahern, the Taoiseach's daughter, and Nicky Byrne of the Westlife boy band, will wed this afternoon at the Church of St Peter and St Paul in Gallardon, 75 km south of Paris. Both are 24 years old.
The ceremony will be followed by an overnight reception for 400 guests at the nearby Château d'Esclimont.
France's record-breaking hot spell has been the main concern of wedding organisers. In the cobblestone streets of Gallardon, temperatures have reached 40 degrees, and air conditioning had to be installed in the giant marquee on the lawn at the Château d'Esclimont. "Nicky said that what was an option had become an absolute necessity," said Ms Joanne Byrne, the couple's wedding co-ordinator and spokeswoman. The thick stone walls of the 12th century church keep temperatures down.
The €1 million cost of the lavish wedding will be covered by an exclusive contract with Hello! magazine for the same amount. In the quest for secrecy, the château agreed not to divulge anything about the reception. Westlife fans and the public will have to wait until Hello! reaches newstands on Wednesday for photographs and descriptions of the day.
Gallardon, population 3,680, is a proud little town. At the town hall, the mood is a mixture of amusement at the sudden attention from Irish and British media, and hurt feelings that local officials were not included in preparations.
"Usually, couples get married here in the mairie before going to the church," said acting mayor Mr Paul Holzl (74). "It would have been my job to marry them." To get around the French residency requirement, the couple held their civil ceremony in Wicklow four days ago.
The bride tried in vain to avoid drawing attention to the church wedding. "Everybody in town knows about it," said Mr Frédéric Aviceau, an administrative assistant at the town hall. "Special agreements have been made with the gendarmerie and the CRS (riot police) to keep onlookers away. The main street and several others will be blocked, to keep the townspeople from seeing. Shopkeepers are griping because they won't be able to sell anything."
The delivery of a grand piano to the church yesterday was the talk of Gallardon. Shortly before the 2 p.m. ceremony, residents expect two coaches to pull up on Cloister Square, carrying wedding guests from hotels in Chartres.
It is as if a piece of Ireland were being transplanted to the Beauce plateau for the day. The food and drink will be Irish and all important roles - including the priest - will be played by Irish people. The French will barely get a look in.