Instead the pilot returned to the Villacoublay air base outside Paris as a precaution, Defense Ministry spokesman Gerard Gachet said. The president and his entourage were transferred to another aircraft, a Falcon 900, and left.

It’s not unusual for planes to be struck by lightning when traveling through thunderstorms; often pilots will fly at higher altitudes to go “above the weather” and in most cases land without difficulty. In March, four planes were struck by lightning the same night during heavy storms near Houston, but all landed without incident.

Hollande’s trip was a postwar custom for new French leaders to reach out to German counterparts to solidify European unity. While new figures Tuesday showed the eurozone has avoided a new recession, thanks largely to Germany, political turmoil in Greece was reviving fears about the fate of the euro.

Hollande, elected May 6 as France’s first Socialist president since Francois Mitterrand left office in 1995, rode to the presidency on a wave of resurgent leftist sentiment amid Europe’s debt woes and protests against capitalism around the world.

The 57-year-old displayed his populist touch in between Tuesday’s ceremonies, stopping for handshakes — and even a kiss — with adoring fans.

Hollande was greeted by Sarkozy Tuesday on the red-carpeted steps of the 18th-century Elysee Palace, the traditional residence of French presidents. The two held a 40-minute private meeting when the outgoing president handed over the codes to France’s nuclear arsenal.

The new president immediately acknowledged the challenges he inherits: “a massive debt, weak growth, high unemployment, degraded competitiveness, and a Europe that is struggling to come out of crisis.”

Hollande promised to fight financial speculation and “open a new path” in Europe. He has pushed back against a European budget-cutting pact championed by Merkel and Sarkozy.

“To overcome the crisis that is hitting it, Europe needs plans. It needs solidarity. It needs growth. To our partners, I will propose a new pact that will tie the necessary reduction of public debt with the indispensable stimulus of the economy,” he said.

Hollande also pledged to bring “dignity and simplicity” to the presidential role — something voters felt that Sarkozy did not always do.

The French mood is glum. Many voters looked to the inauguration as a rare moment of national pride and to Hollande’s presidency as a new opportunity to make things better.

Earlier Tuesday, the state statistics agency released figures showing that the French economy had failed to grow in the first quarter. Some economists predict a contraction ahead, which would complicate Hollande’s promises to rein in the deficit.

World markets and other European leaders will watch closely to see whether Hollande follows through on campaign promises, such as pulling French troops out of Afghanistan by year’s end, freezing gasoline prices and hiking taxes on the rich.

Observers expect that once he settles into the presidency, he’s likely to fall back into the moderate consensus-building that has characterized his career.

Hollande’s relationship with Merkel, the German chancellor, will be crucial to his presidency and the appointment of Ayrault (ay-ROW) as prime minister may well prove an advantage for this relationship. Ayrault, who leads the Socialists in Parliament, is a German speaker and a former teacher of the language of Goethe.

Ayrault is expected to announce a government Wednesday or Thursday. But its future will depend on the outcome of parliamentary elections next month, and whether leftists take control of the National Assembly.

In Tuesday’s ceremony, Hollande received the insignia of the Grand Croix of the Legion of Honor and the necklace of the Great Master of the Order of the Legion of Honor. Each linked medallion of the necklace bears the name of a president, with Hollande’s name recently added.

Hollande shook hands with many of the hundreds at the ceremony then reviewed troops in the palace gardens. Following tradition, 21 shots were fired from cannons at the Invalides, a domed complex on the opposite side of the Seine that holds Napoleon’s tomb.

Rain started pouring down on the famed Champs-Elysees avenue as Hollande rode up its center, standing in the sunroof of his hybrid Citroen DS5, trailed by dozens of Republican Guardsmen on horseback and motorcycle. His suit was visibly drenched within moments. He then headed for the Arc de Triomphe, and its monument to the unknown soldier.

His second presidential speech of the day focused on education, as he pledged to create 60,000 new teaching jobs in the aftermath of cuts Sarkozy had made.

Hollande, who has never been married, was joined for the ceremonies and in his motorcade Tuesday by his poised girlfriend, journalist Valerie Trierweiler. She wore a black dress with translucent sleeves and a white tunic jacket by French label Apostrophe.

Hollande’s former partner and the mother of his four children, Segolene Royal, joined him later Tuesday in a ceremony at Paris City Hall. Royal, a prominent Socialist politician, was runner-up to Sarkozy in 2007; she is angling for a top political job under Hollande’s presidency.

Hollande’s first presidential meal reflected relative modesty, at least by French culinary standards: lobster and citrus terrine, cote de boeuf, and strawberry macaron cookies for dessert.

Sarkozy left the palace hand-in-hand with wife Carla Bruni-Sarkozy, had a last handshake on the palace steps with Hollande, then was driven away. Former staff members gathered in the palace courtyard applauded loudly as Sarkozy left, and fans at the Elysee gates waved signs reading “Nicolas, merci!”

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Geir Moulson in Berlin, Cecile Brisson, Jamey Keaten and Thomas Adamson in Paris and Joan Lowy in Washington, D.C., contributed to this report.