JUILLAC, France – When the widow and younger son of a late socialist president, Francois Mitterrand, were discovered as sharply divided over the E.U. constitution, news of the split struck a chord in households across France.

Gilbert Mitterrand spoke of heated debate late into the night as he tried in vain to persuade his mother, Danielle, of the virtues of the document.

A short drive east from the winegrowing town of which Mr. Mitterrand is mayor, Libourne, Elvina Biganeau and Vincent Zecchini have been grappling with the “incomprehensible” 191-page text delivered to every home by the government. As parents of two small children, looking forward to their wedding in July, and proud of their beautiful home in Juillac, they hardly seem a couple at war. But Ms. Biganeau, 29, a committed socialist, will register a firm “No” in Sunday’s referendum, while her 33-year-old husband-to-be, who supports President Chirac’s ruling center right UMP, expects to vote without the least enthusiasm for the Yes camp.

The disagreement that currently inspires lively debate in the family’s home is typical of households split down the middle by the referendum.

Serving a delicious meal of locally raised duck, Ms. Biganeau articulated her opposition to the treaty.

“We already have serious problems in France with the relocation of businesses, or the major parts of them, to countries in Eastern Europe or North Africa, where labor and costs are cheap,” she said. “I have no doubt that the phenomenon would be enormously aggravated under this treaty. It is designed for the interests of employers, who are already very good at leading Chirac and his government around the political stage like dogs on a leash.”

Ms. Biganeau says she fears for the future of her children, Lea, 5, and Victor, 2, if approval of the constitution leaves them growing up in a Europe obsessed by competition and capital.

“I don’t approve of socialist leaders who I supported to the hilt only to see them betray their principles,” she said. “But I am still a great admirer of Francois Mitterrand and believe his widow when she says he would have voted “No.”

“Like him, I believe everyone has the basic right to a decent life. Vincent and I agree on that but he is more persuaded that it comes from having money whereas I say money is already too much of a driving force.”

To hear Mr. Zecchini’s defense of the “Yes” campaign is not to listen to a man gripped by the conviction with which Mr. Chirac commends the constitution.

Mr. Zecchini, who manages the furnishings department at a local store, is angry at his loss of spending power in recent years. He feels let down by Mr. Chirac’s 10 years in office and shares his wife’s fear of “social dumping,” as Polish plumbers and Portuguese builders take work from better-paid French workers. He said he was angry that the government had left it to the people to decide the constitution’s fate, a comment that provoked his fiancee’s instant riposte: “Speak for yourself.”

“No,” he continued. “Our parliament should have taken the decision. Look at this document: the close typing and the six-line sentences. We struggle to understand it and I bet 97 or 98% of the French find large parts incomprehensible. Europe needs to be strong and I am afraid of the unknown if we are not part of it. France is not yet economically strong enough to stand up by itself to America, Japan, and the other big economic powers.”