In "Two Friends," what is some flashback?

Maupassant uses one fairly long flashback at the beginning of the story. The two friends, Monsieur Morissot and Monsieur Sauvage, happen to meet on the street in famine-ravaged Paris which is being besieged by the invading Prussians. As soon as the two old friends meet, Maupassant immediately launches into a flashback which is obviously intended to contrast happier times of peace with the terrible suffering and destruction being wrought by the invaders. The flashback begins with the third paragraph.

Before the war broke out Morissot had been in the habit, every Sunday morning, of setting forth with a bamboo rod in his hand and a tin box on his back. He took the Argenteuil train, got out at Colombes, and walked thence to the Ile Marante. The moment he arrived at this place of his dreams he began fishing, and fished till nightfall.

The entire flashback does little more than describe how the two friends enjoyed their fishing in the beautiful surroundings. It characterizes them as simple, peaceful, unaggressive Frenchmen who will eventually be shown in contrast to the hateful Prussians who capture them while they are innocently fishing. The flashback comes to an end with the following:

Monsieur Sauvage would sometimes smile at Morissot, and say:

"What a glorious spectacle!"

And Morissot would answer, without taking his eyes from his float:

"This is much better than the boulevard, isn't it?"

Then the author returns to the present with the words:

As soon as they recognized each other they shook hands cordially, affected at the thought of meeting under such changed circumstances.

When they decide to take the risk of going fishing at their favorite spot on the river, the expedition has a more serious purpose than it had ever had before. Maupassant opens his story with a description of the starvation experienced by the people of Paris during the Franco-Prussian War (July 1870-May 1871).

Besieged Paris was in the throes of famine. Even the sparrows on the roofs and the rats in the sewers were growing scarce. People were eating anything they could get.

If the two friends can return to Paris with a big catch of fish, it will be a bonanza for both of them. They will be able to enjoy a big dinner for the first time in months. They seem to have little trouble catching a whole bag of fish. This is understandable because the war has prevented Frenchmen from doing much fishing in the area and the fish have multiplied. But it turns out that the evil Prussian officer ends up enjoying their fish after he has them both executed for refusing to divulge the password they were given to enable them to get back through the French defenses into the city.

The method of narration is anonymous third-person dual character point of view. Maupassant uses the points of view of two characters partly in order to emphasize the patriotism of Frenchmen who love peace but are willing to sacrifice their lives rather than cooperate with the hated Prussians. The French were soundly defeated and humiliated in the Franco-Prussian War and conceived a long-lasting hatred for Prussians and Germans. Maupassant wrote a number of short stories in which he expressed his own hatred. His most famous story of that type is "Boule de Suif," which launched his successful literary career.