The first was for the development of tidal arrays in Alderney's waters.
The second involves the development of an electricity interconnector cable between France, Alderney and Britain.
Paul Clark, chief executive officer, said it was a move towards the creation off Alderney of one of Europe's largest tidal stream developments.
Alderney Renewable Energy (ARE) was set up in 2004 and holds an exclusive licence to commercially develop tidal and wave power around the coast of the northern most of the Channel Islands.
The first agreement was signed with French industrial group DCNS and the second with ARE, its partner Transmission Capital and the French grid operator RTE.
ARE said the electricity interconnector cable between France, Alderney and Britain would enable the export of up to four gigawatts of tidal power from Alderney.
It said the cable, known as the FABLink, could also be used as a power trading link between the two countries.
The agreements were signed at the Anglo-French summit held in Paris, with the French Industry Minister Eric Besson and the UK Energy Secretary Ed Davey signing on the behalf of their governments.
Mr Davey said: "We are determined to promote the potential of marine energies. We welcome the plan for a tidal turbine farm off Alderney in the Channel Islands."
He said: "We believe this project could encourage the emergence of industrial co-operation between France and the UK, while opening up new international prospects.
"We acknowledge the importance of developing new electricity interconnectors between our two countries in order to strengthen further the linking of our grids, improve the security of our energy supplies and facilitate the integration of intermittent energy sources."

Hussain, who won 2015's Great British Bake Off, will judge alongside chef and food writer Allegra McEvedy.
CBBC's Junior Bake Off sees 40 youngsters aged nine to 12 competing for the title.
Hussain said: "This time last year I was in the Bake Off tent and now I get to go back and help encourage the next generation to get their bake on."
The contestants will each complete two bakes over 10 heats, including a technical bake and showstopper challenge, with four youngsters in the grand final.
The CBBC show's previous judges have included Mary Berry, Paul Hollywood, James Martin and Graham Hornigold.
Hussain, 31, has built a career since winning Bake Off which includes her first cook book, a column for The Times and a request from Buckingham Palace to make a cake for the Queen's 90th birthday. She will also present The Chronicles of Nadiya, a TV show tracing her culinary roots in Bangladesh.
She won last year's final on BBC One after baking a "big fat British wedding cake" adorned with jewels from her own wedding day as the showstopper.
It became the most-watched TV programme of the year with an average audience of 15.1 million people, according to consolidated figures, which include catch-up viewing.
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Two agreements have been signed aimed at creating one of the most significant tidal power sites in Europe, Alderney Renewable Energy has announced.
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Former Bake Off winner Nadiya Hussain has said she is "excited" to be joining the show's junior version as a judge.