For Chad's 64-year-old ruler, the ceremony was largely a formality. A former commander-in-chief of the army, the autocratic Deby has been in power for 26 years. Foreign powers respect him. Chad is seen as a relatively stable country in an unruly region. Chad possesses well-trained security forces, which Deby keeps on a tight rein. His troops are deployed in Nigeria, Niger and Cameroon, where they are battling the Boko Haram Islamist insurgency.

Chad's contingent with the UN mission in Mali is larger than all the others, consisting of more than 1,000 troops. European countries count on Deby to control the routes used by refugees leaving Africa.

More than a dozen African heads of state, including the presidents of Nigeria and Niger, allies in the fight against Boko Haram, attended Monday's ceremony.

Deby's troops may enjoy a good reputation abroad, but back home, Chadians are growing increasingly irritated by his leadership style. He ordered the construction of a new luxury hotel for his swearing in ceremony in a country where the prisons are overcrowded and civil servants wait months for their salaries. Hopes of reform have been dashed, Vincent Hendrick from the Catholic relief agency Misereor in Chad told DW.

Chadian troops on an international counterterrorism mission at an army base in N'djamena

Social media restrictions

"I am the president of all Chadians," Idriss Deby said in his inauguration speech in the capital N'Djamena on Monday.

There have been frequent demonstrations calling for Deby's resignation. Six former candidates who failed to unseat him at the last presidential elections are even planning to proclaim a separate government. "Deby's election victory was neither legal nor legitimate," one of the candidates, Saleh Kebzabo, told DW.

The opposition vowed to maintain a general strike throughout Monday following a government crackdown at the weekend.

One young protestor was shot dead on Sunday. Kebzabo said he had been hit by live bullets fired by security forces to disperse the protestors.

Deby was reelected in April 2016 polling 61.5 percent of the vote according to offical figures, which said Kebzabo had garned 12.8 percent.

Kebzabo said no date had been set for the proclamation of a separate administration. "We will announce the counter government when we think the time is right," he said.

The April elections took place amid a climate of repression. Opponents of the regime were jailed for organizing peaceful protests. In the meantime, the situation has deteriorated even further. Since the elections, many Chadians can no longer access social media such as Twitter, Facebook or WhatsApp. "Journalists can't do stories and businesses can't communicate with their customers, many of whom are in different parts of the world," said Julie Owono, who heads the Africa department at the NGO "Internet without Borders."

Protests in N'Djamena against the arrest of politcal oponents of the regime

The Chadian government blames technical problems for the lack of connectivity. However, communications expert Qemal Affagnon is suspicious of this explanation. The government ordered telecommunications operators to restrict access to social media back in January, he told DW. It is technically feasible and similar clampdowns have been imposed during elections in other African countries. But most them were only temporary.

No trust in the government

Chadians complain of restrictions on civil liberties and poor living and working conditions. In the UN Human Development Index for 2015, Chad comes very close to the bottom, occupying the 185th place out of 188. Staff at the national broadcaster ONRTV went on strike recently. "We don't have any free weekends, or days off, anymore," one journalist said. Staff were promised better working conditions in 2011 but nothing has changed in the meantime.

Saleh Kebzabo, opposition candidate for the 2016 presidential election, casts his vote at a polling station in N'djamena

The gang rape of a schoolgirl by the sons of senior officials earlier in the year triggered angry protests around the country, which were dealt with severely by the authorities. The government has also been weakened by the collapse in the price of oil.

Deby is seeking to shore up his defenses. He wanted to take the wind out of the sails of his political opponents by reforming the constitution, but this stratagem misfired. Opposition politicians suspect he wanted to use the reform to create the post of vice president so he could groom a successor, though the ruling party denies this.

Confidence in the government and the authorities generally is at a low ebb. Several dozen military personnel, who were regarded as being critical of the regime, have disappeared since the elections. The public prosecutor issued summonses to two of the unsuccessful presidential candidates, including Saleh Kebzabo, in connection with an investigation into the whereabouts of the military personnel. This made Kebzabo suspicious and he declined to attend the hearing. Through his lawyer, he inquired why he in particular had been summoned. Other people had also openly complained about the disappearances, including the French ambassador, he said.

On Monday, however, the French Defense Minister Jean-Yves Le Drian was among the guests at Deby's inauguration. Kebzabo told AFP he was "surprised and disappointed" by France's decision to send a high ranking representative.