The latest contracts underscored how Doha can use the wealth it has accumulated as the world's biggest exporter of liquified natural gas to defy some of the largest and wealthiest Arab countries.
Saudi Arabia, the United Arab Emirates, Bahrain and Egypt cut diplomatic and trade relations with the emirate almost six months ago. They accuse the Qataris of backing terrorism, which Qatar denies.
"Our position on this blockade was very clear. Qatar’s position was very clear - to resolve this problem, if we saw problems between us and our neighbours - we should be at a table and speak honestly," Emir Sheikh Tamim bin Hamad al-Thani said at a news conference alongside French President Emmanuel Macron.
Macron, who has tried to play a mediation role between the sides, was in Doha to discuss how to combat the financing of terrorism at a time when the Middle East is locked in a regional power struggle between Sunni Saudi Arabia and Shi'ite Iran.
"Restoring stability to the Gulf is a priority for us because we have a lot of friends here," Macron said. "Our wish is that we find a quick resolution to today's situation."
Paris has strong commercial and political ties with Qatar. It has promoted deeper business interests in the country and encouraged Qatari investment in France, where the Gulf state already has assets of about $10 billion.
Macron said some 12 billion euros ($14.13 billion) worth of deals were agreed on Thursday. They included Qatar's taking up an option from 2015 to buy 12 more Dassault Aviation-made Rafale fighters, and saying it could purchase a further 36. It has already bought 24 planes for about 6 billion euros, including missiles.
It also committed to buying 490 armoured vehicles from defence firm Nexter.
Doha has repeatedly called for dialogue with its neighbours, although it has strengthened its military as relations with them have deteriorated. It has secured this year alone military equipment deals with the United States, Russia and Britain.
"In total, it amounts to nearly 12 billion euros which was signed today and which underlines the closeness of our economic cooperation," Macron said.
Among other deals signed, SuezA will dredge and clean Qatar's lagoon and a rail consortium of RATP and SNCF will build and operate a metro system in the Qatari capital.
Qatar Airways also placed a new order for Airbus A321neo civilian aircraft to replace an earlier A320neo order. The new deal for larger planes is worth an extra $930 million at current list prices for Airbus and involves a switch of engine supplier to a French-American venture co-owned by Safran< and General Electric.
(Additional reporting by Jean-Baptiste Vey and Tim Hepher, writing by John Irish, editing by Richard Lough, Larry King)
By Hadeel Al Sayegh