Paris reached a population of 200,000 by the year 2850BC. 17% of the world's population lived under French rule. Unrest was beginning to stir, and a prohibitively large portion of the city's income had to be diverted to entertainment. It was time to send off some of the population to found new cities.
Before that could happen, a strong military was necessary. The sages predicted that they could create even better weapons by researching iron working, but that would take a long time. Instead, they decided to develop archery first.
During the time required to make preparations for expansion, the city council did everything possible to keep the citizens working, while dedicating as many resources as possible to the sages' work.

[size=-2]View of Paris in 2850BC. There is evidence that the city council made very precise budget calculations
based on projected revenue, so that as much commerce as possible could be put into research.[/size]

[size=-2]View of Paris in 2800BC. With the ever growing population there was also a steady increase in production.[/size]
The training of spearmen continued at a fast pace. It seemed defenses would be ready just in time. In 2670BC, a new enemy was met: the Persians. Around this period, the Persians were not very well developed. They had two cities, and didn't even possess the knowledge of an alphabet.

[size=-2]View of France in 2670BC. The Aztec warriors had been moving around at
the borders indecisively. New reinforcements were now underway.[/size]
The Aztecs continued forward this time, and began the first siege of Paris.

Prelude
By 2630BC, the enemy had finally reached the gates of Paris. Under the leadership of Quentin le Petit, the French troops had continued to harass the approaching troops, forcing them to move around so they would not be able to disrupt French trade. The Aztecs finally settled in les Champs de Mars, the fields of the god of war.
Les Champs de Mars were at that time of no commercial importance to the French. The lands were not cultivated, and there weren't even roads. There were important roads south and east of Paris, which allowed the French to move quickly. It was decided the French would defend against the main attack at the walls of Paris this time.
Battle
Quentin le Petit wanted to make sure the Aztecs would continue to approach following the same route. His warrior group made a preemptive strike against the arriving troops, before they could fortify. Because the Aztec troops in the Champs de Mars were much weakened after this battle, their reinforcements had no choice but to continue to the same area, and not make a detour to pillage the French lands. About 3000 Aztec warriors were slaughtered before Quentin's troops became too depleted to press on. There were about 2000 casualties on French side.

[size=-2]French troop movements and counterattack at the start of the First Siege[/size]
The spearman divisions that had been guarding the cultivated lands moved back to Paris, to further strengthen defenses. To the east, the Persian spearman division that had made first contact, did start to move in the direction of Paris, bent on disrupting the French peasants' activity. They were still some distance away though, and would not be a factor in the battle.

[size=-2]Aztec troops are in position to attack Paris. The Persians are approaching from the northeast.[/size]
In 2590BC, the Aztecs made their attack. They were hopelessly outnumbered, and had inferior troops. A single unit of spearmen, led by Colonel Contrepied, defeated the attacks of two warrior units that attacked the center of the French defenses. The Aztecs lost 6000 warriors at the walls of Paris, among them the great warrior Ansar. The Aztec contingent of archers didn't attack at all. The French incurred practically no losses. Contrepied's unit became the elite spearman unit of the French army.

[size=-2]The Aztec archers are completely surrounded. The Persians find their pillaging target protected by French troops.[/size]
Aftermath
The siege had taken very much out of the Aztec army. Prior to the battle, the sizes of the French and Aztec armies were comparable, but after the desperate attack the French were markedly stronger. The people offered Joan an expansion to her palace.

[size=-2]Painting of Joan's palace around 2550BC, after the First Siege of Paris[/size]