The article is devoted to the one of the most important periods of the history of the Egyptian campaign of the French army of Orient from August to December 1799. Then, after the flight from Egypt of Napoleon Bonaparte, his successor, General Kleber, was compelled to urgently take over the leadership of the troops and the occupation administration while trying to prevent the invading of the Ottoman army from Syria. The perfectly conceived military and political combination of Kleber, who sought to play on the contradictions of the powers of the anti-French coalition, collapsed due to a number of circumstances that did not depend on him, in particular, because of the catastrophic fall of morale of the French occupation troops after a year of their stay in the Orient. The result of the diplomatic failure of Kleber was the fall of the French frontier fort El Arish, which proved to be one of the bloodiest defeats of the army of Orient during the Egyptian expedition.