What mood does the first chapter of Dickens' A Tale of Two Cities set?

The first chapter of A Tale of Two Cities begins with one of the most immortal opening phrases in English literature: "It was the best of times, it was the worst of times..." The opening paragraph goes on to refer to an "epoch" of both faith and "incredulity," of hope and despair. The opening chapter goes on to evoke such paradoxes in order to describe an era where powerful forces that historians and social scientists would later describe as "structural" would tear the lives of the people of London and Paris apart. This was an era of extreme wealth and extreme poverty. Dickens does mention a number of differences between France and England, especially as relates to religion and criminal justice, but the social problems that plague both countries are described as very serious and pervasive, all the more so since they exist alongside wealth and privilege. In short, the first chapter strongly suggests that conflict is imminent, yet the characters in the story carry on unaware:

Thus did the year one thousand seven hundred and seventy-five conduct their Greatnesses, and myriads of small creatures—the creatures of this chronicle among the rest—along the roads that lay before them.
https://www.owleyes.org/text/tale-of-two-cities/read/chapter-i-the-period