The National Front failed to build on first round leads in the French regional elections and did not win any councils, according to exit polls.
Marine Le Pen's far-right party had been leading in three target regions heading into Sunday's run-off.
Both she and niece Marion Marechal-Le Pen lost out in their respective regions, pollster said.
Three polling agencies projected that the opposition conservatives and governing Socialists won control of France's 13 regions.
The National Front - traditionally an outcast in the mainstream political scene - has been boosted by the migration crisis and the Paris terror attacks.
But their hopes of winning two of its target seats were dented when the Socialists withdrew and urged supporters to back Nicolas Sarkozy's conservatives.
The vote is seen as key for all three 2017 hopefuls: Ms Le Pen, President Francois Hollande, and former president Mr Sarkozy.
The regional councils in France are responsible for education, public transport and other administrative sectors.
Le Pen took to Twitter to thank her supporters, taking aim at her rival parties, particularly Francois Hollande's Socialists:
"Dans ses bastions du Nord et du Sud, nous avons éradiqué un @partisocialiste malfaisant." #NPDCP
— Marine Le Pen (@MLP_officiel) December 13, 2015
