Caroline Garcia and Kristina Mladenovic put their doubles differences aside to send France through to the Fed Cup final, with world number two Simona Halep unable to inspire Romania to victory in the deciding match.
A fifth rubber was needed for the semi-final after both nations won one singles matches each on Sunday, and Halep stepped up to play her first Fed Cup doubles match in two years due to an injury to Irina-Camelia Begu.
Halep and her partner Monica Niculescu won the first set but Garcia and Mladenovic, doubles winners at the 2016 French Open before an acrimonious split, fought back to seal a 5-7 6-3 7 6-4 success in their first match together in two and a half years.
France, into their sixth final and seeking their first Fed Cup title since 2003, will now travel to Australia after they also won 3-2, against Belarus, earlier on Sunday.
Halep, who had beaten Mladenovic in straight sets in the first singles rubber on Saturday, restored Romania's lead in the tie when she prevailed against Garcia 6-7 (6-8) 6-3 6-4 in Sunday's first match.
Yet a decider was needed when Pauline Parmentier won for the first time in five Fed Cup matches, emerging victorious 6-3 2-6 6-2 against Begu, who injured her right ankle and was unable to take part in the doubles.
That meant Halep was forced into action against the French duo, who have a frosty relationship following a row three years ago when Mladenovic accused Garcia of lacking "courage or human values" over the manner of their split.
Yet the two reprised their doubles partnership on Sunday and Halep's double-fault when her opponents had break point at 4-4 in the decider proved costly as Garcia served out to clinch the match before embracing Mladenovic.