Lutetia

The siege of Paris of 845 was the culmination of a Viking invasion of West Francia. The Viking forces were led by a Norse chieftain named "Reginherus", or Ragnar, who tentatively has been identified with the legendary saga character Ragnar Lodbrok. Reginherus's fleet of 120 Viking ships, carrying thousands of men, entered the Seine in March and sailed up the river. The Frankish king Charles the Bald assembled a smaller army in response but after the Vikings defeated one division, comprising half of the army, the remaining forces retreated. The Vikings reached Paris at the end of the month, during Easter. They plundered and occupied the city, withdrawing after Charles the Bald paid a ransom of 7,000 French livres [2,570 kg (83,000 ozt)] in gold and silver.

Île de la Cité (French: [il də la site]; English: City Island) is an island in the river Seine in the center of Paris. In the 4th century, it was the site of the fortress of the Roman governor. In 508 Clovis I, the first King of the Franks, established his palace on the island. In the 12th century it became an important religious center, the home of Notre-Dame cathedral, and the royal chapel of Sainte-Chapelle, as well as the city's first hospital: the Hôtel-Dieu. It is also the site of the city's oldest surviving bridge, the Pont Neuf. With the departure of the French kings to the Louvre Palace and then to the Palace of Versailles, the island became France's judicial centre. In 1302 it hosted the first meeting of the Parliament of Paris and was later the site of the trials of aristocrats in the French Revolution. Today, it is the home of the Prefecture de Police, the Palais de Justice, and the Tribunal de commerce de Paris. The Mémorial des Martyrs de la Déportation, a memorial to the 200,000 people deported from Vichy France to the Nazi concentration camps during the Second World War, is located at the eastern end of the island. The city's most famous landmark, Notre-Dame de Paris, was badly damaged by a fire in 2019 and is closed, but it is expected to reopen in time for the Paris Olympics in 2024. As of 2016, the island's population was 891.

The place Louis-Lépine is a square in the 4th arrondissement of Paris on the île de la Cité. It is bounded by the rue de la Cité (east), rue de Lutèce (south), rue Aubé (west), the quai de la Corse (north), and is crossed by the allée Célestin-Hennion. It is named after Louis Lépine, a notable prefect of the Paris police. The Metro station Cité has its only entrance on the square. It is the venue for the Marché aux fleurs Reine-Elizabeth-II, a flower and bird market. The prefecture of police is a large building located between the Place Louis Lépine and the Quai du Marché neuf. This building was built as a barracks for the Garde républicaine from 1863 to 1867 (architect Pierre-Victor Calliat) and was occupied by the Prefecture in 1871.

The Marché aux fleurs Reine-Elizabeth-II is a flower market in Paris. It was formerly known as the Marché aux fleurs et aux oiseaux Cité but was renamed for Queen Elizabeth II after a state visit in 2014.It sells caged birds on Sundays but this trade has been forbidden on the grounds of animal welfare and so is expected to cease after a period of renovation and reorganisation scheduled from 2023 to 2025.

The police prefecture (French: préfecture de police) is the unit of the French Ministry of the Interior that provides police, emergency services, and various administrative services to the population of the city of Paris and the surrounding three suburban départements of Hauts-de-Seine, Seine-Saint-Denis, and Val-de-Marne. It is headed by the Prefect of Police (Préfet de police). "La PP" (Préfecture de Police), as it is also known, supervises the Paris Police force, the Paris Fire Brigade, and various administrative departments in charge of issuing ID cards and driver licenses or monitoring alien residents. The Prefecture of Police also has security duties in the wider Île-de-France région as the Préfet de Police is also Préfet de Zone de Défense (Prefect for the Defense zone). Since 2017, it has acquired direct responsibility for the three main airports of the Paris area (Charles de Gaulle, Orly and Le Bourget). In addition to the Préfecture de Police, the French government created the Paris Municipal Police (French: Police municipale de Paris) in 2021. In contrast with the Préfecture, the municipal police report to the city government, rather than to the national government. Municipal police officers began patrolling city streets on foot, bicycle, and by car starting on October 18, 2021. The goal of the municipal police is to "make neighbourhoods safer and more peaceful and ensure that public space is shared," for example by enforcing laws on parking, littering, breaking up quarrels, and assisting homeless or elderly residents.The préfecture is a large building located in the Place Louis Lépine on the Île de la Cité. This building was built as a barracks for the Garde républicaine from 1863 to 1867 (architect Pierre-Victor Calliat) and was occupied by the Prefecture in 1871. As it is the capital of France, with government assemblies and offices and foreign embassies, Paris poses special issues of security and public order. Consequently, the national government has been responsible for providing law enforcement and emergency services since the creation of the Lieutenancy General of Police (lieutenance générale de police) by Louis XIV on March 15, 1667. Disbanded at the start of the French Revolution in 1789, it was replaced by the current Prefecture of Police created by Napoléon I on February 17, 1800. This means that, up until 2021, Paris did not have its own police municipale and that the Police Nationale provided all of these services directly as a subdivision of France's Ministry of the Interior. Policemen assigned to "la PP" are part of the Police nationale but the Police Prefect reports directly to the Interior Minister, not to the director of the Police nationale (Directeur général de la Police nationale or DGPN). In Parisian slang, the police were sometimes known as "the archers", a very old slang term in reference to the archers of the long-defunct Royal Watch. Paris also has the "Direction de la Prévention, de la Sécurité et de la Protection" (DPSP) (Prevention, Security and Protection Directorate) which is composed of Agents with municipal police powers titled inspecteurs de sécurité (Security Inspectors). The DPSP reports to the Mayor of Paris.

The siege of Paris of 885–886 was part of a Viking raid on the Seine, in the Kingdom of the West Franks. The siege was the most important event of the reign of Charles the Fat, and a turning point in the fortunes of the Carolingian dynasty and the history of France. It also proved for the Franks the strategic importance of Paris at a time when it also was one of the largest cities in West Francia. The siege is the subject of an eyewitness account in the Latin poem Bella Parisiacae urbis of Abbo Cernuus. With hundreds of ships, and possibly tens of thousands of men, the Vikings arrived outside Paris in late November 885, demanding tribute. This was denied by Odo, Count of Paris, despite the fact he could assemble only several hundred soldiers to defend the city. The Vikings attacked with a variety of siege engines but failed to break through the city walls despite days of intense attacks. The siege was maintained for months but without any significant assaults after the initial attack. As the siege continued, most of the Vikings left Paris to pillage further upriver. The Vikings made a final unsuccessful attempt to take the city during the summer. In October, Charles the Fat arrived with his army. To the frustration of the Parisians who had fought to defend the city, Charles stopped short of attacking the Viking invaders. Instead, he allowed them to sail further up the Seine to raid Burgundy (which was in revolt) and promised a payment of 700 livres (257 kg) of silver. Odo, highly critical of this, attempted to defy Charles' promises. When Charles died in 888, Odo was elected the first non-Carolingian king of the Franks.

Sainte-Geneviève-des-Ardents (French pronunciation: ​[sɛ̃t ʒə.nə.vjɛv də.z‿aʁ.dɑ̃]), known as Sainte-Geneviève-la-Petite in the Middle Ages, was a church located at present-day Parvis Notre-Dame – Place Jean-Paul-II in the Île de la Cité in Paris, France. It is dedicated to Saint Genevieve, the miracles imputed to whom included "the cessation of a horrible plague, called the mal ardent, which desolated Paris in the reign of Louis le Gros".

Saint-Denis de La Chartre (French: église Saint-Denis-de-la-Chartre or église du prieuré Saint-Denis-de-la-Chartre) was a Roman Catholic church building located on the Île de la Cité in Paris, France. It was demolished in 1810.

Cité (French: [site] (listen)) is a metro station on Line 4 of the Paris Métro in the 4th arrondissement of Paris.

On 6 June 2017, at around 16:00 CET, French police shot a man who attacked a police officer with a hammer outside Notre-Dame de Paris cathedral on the Île de la Cité, located in the centre of Paris. The man injured the officer with the hammer, and was found to be in possession of kitchen knives. French police opened a terrorism investigation.The accused is an Algerian-born journalist named Farid Ikken, who won an award for his prize-winning human rights writing in Sweden, before returning to Algeria where he started an online news site, and then, moved to France on a student visa, he was pursuing a PhD in communications at the time of the attack. According to the prosecutor, a video in which he pledged allegiance to ISIS was found at the accused's apartment.

The Hôtel-Dieu (French pronunciation: ​[otɛldjø]) is a hospital located on the Île de la Cité in the 4th arrondissement of Paris, on the parvis of Notre-Dame. It was supposedly founded by Saint Landry in 651 AD, making it the oldest hospital in the city and the oldest worldwide still operating. The Hôtel-Dieu was the only hospital in the city until the Renaissance. While the old Hôtel-Dieu stood by the Seine on the opposite side of the parvise, it was ravaged by fire several times, and was rebuilt for the last time at its present location between 1867 and 1878, as part of Haussmann's renovation of Paris. Nowadays operated by Assistance publique – Hôpitaux de Paris (AP-HP), the Hôtel-Dieu is also a teaching hospital associated with the Faculté de Médecine Paris-Descartes.

In France, the tribunal de commerce (plural tribunaux de commerce, literally "commercial courts") are the oldest courts in the French judicial organization. They were created at the end of the Middle Ages. The commercial court has jurisdiction over commercial cases: disputes between merchants, disputes over commercial acts, controversies involving commercial corporations, and bankruptcy proceedings. The judges of the commercial courts are not career judges but elected traders. They are elected for terms of two or four years by an electoral college made up of current and former judges of the commercial courts and traders’ delegates (délégués consulaires), who are themselves traders elected in the area within the jurisdiction of the court. There are 134 commercial courts in France.