France, Jan. 29 -- The bill had easily passed the lower National Assembly last year but was heavily amended in the upper house after often angry and chaotic debate led by right-wing and centrist senators.

Supporters said the changes stripped the text of its purpose.

"The debate, which should have remained dignified and deeply humanist, has turned into a dogmatic and political battle," Patrick Kanner, head of the Socialist Party in the Senate, said ahead of Wednesday's vote.

Centrist senator Loic Herve said opponents of assisted dying could not be expected to support the text.

"You can't ask senators who are opposed to euthanasia and assisted suicide to vote for an article like" the one adopted by the National Assembly, he said. The Se...