PARIS (Reuters) - French President Emmanuel Macron said on Tuesday that Europe needed a significant minimum carbon price to boost investment in its energy transition, and a European carbon tax at the bloc’s borders to guarantee fair competition for its companies.

Presenting a series of proposals to reform the 28-nation European Union, Macron said Europe had to give “the right price signal” for carbon emissions, and make them sufficiently high enough to attract investments.

He said that a carbon price below 25 to 30 euros ($35.31) per ton was not efficient to spur investments in renewable energy and energy efficiency.

“If in the years ahead, we don’t have a significant price of carbon per ton to allow for a profound change in our economies, then it would be worthless,” Macron said in his speech. “We must work toward that horizon. From today, we must organize ourselves and do it. It is indispensable.”

Macron added that the ecological transition he was proposing also required Europe to have a common energy market and to develop more electricity interconnections.

France has been calling for a European carbon floor price which would help curb carbon dioxide emissions, particularly from coal-powered generators, and increase investments in renewable and other cleaner sources of energy.

The previous government abandoned a plan to set a carbon price mechanism targeting coal-fired power plants in France, saying it ran foul of European mechanisms and could hurt jobs.

France has also been pushing for a reform of the carbon European Emissions Trading System (ETS). Carbon prices under the system, which charges companies for each ton of carbon dioxide they emit, have fallen to about 7 euros a ton from about 30 euros in 2008 because of a glut of permits.

December 2017 expiry EU carbon permits were down 4.12 percent to 6.98 euros a ton on Tuesday.

France and Germany said earlier this month that they would work together on measures to reinforce carbon pricing in the European electricity sector and want an agreement on the European Union’s carbon market reform by November.