{
  "contentStorage": "postgres",
  "title": "Paris Metro Line 4 · Relations",
  "description": "Paris Metro Line 4 is a north-south trunk line, starting from Porte de Clignancourt in the north to Bagneux–Lucie Aubrac in the south, and has achieved fully automated operation.",
  "url": "/en/concepts/paris-metro-line-4/relation.html",
  "entity": {
    "customFields": [
      {
        "key": "line_opened",
        "value": "April 21, 1908"
      },
      {
        "key": "line_length",
        "value": "Approximately 14 kilometers"
      },
      {
        "key": "line_termini",
        "value": "Porte de Clignancourt ↔ Bagneux–Lucie Aubrac"
      },
      {
        "key": "line_structure",
        "value": "Underground (outdoor crossing over the Seine between Cité and Saint-Michel)"
      },
      {
        "key": "line_max_speed",
        "value": "70 km/h"
      },
      {
        "key": "line_status",
        "value": "In operation"
      },
      {
        "key": "line_operator",
        "value": "RATP"
      },
      {
        "key": "line_owner",
        "value": "RATP"
      },
      {
        "key": "line_rolling_stock",
        "value": "MP14"
      }
    ],
    "id": "concept_paris_metro_l4",
    "type": "concept",
    "title": "Paris Metro Line 4",
    "slug": "paris-metro-line-4",
    "summary": "Paris Metro Line 4 is a north-south trunk line, starting from Porte de Clignancourt in the north to Bagneux–Lucie Aubrac in the south, and has achieved fully automated operation.",
    "status": "published",
    "categories": [
      "category-transit"
    ],
    "tags": [
      "tag-metro"
    ],
    "sources": [
      {
        "id": "wiki_ligne_4_du_m_c3_a9tro_de_paris",
        "title": "Ligne 4 du métro de Paris — Wikipédia",
        "url": "https://fr.wikipedia.org/wiki/Ligne_4_du_m%C3%A9tro_de_Paris"
      },
      {
        "id": "ratp",
        "title": "RATP Group — RATP en Île-de-France",
        "url": "https://ratpgroup.com/the-ratp-group/entities/ratp"
      }
    ],
    "createdAt": "2026-10-28T00:00:00+08:00",
    "updatedAt": "2026-10-28T00:00:00+08:00",
    "updatedBy": "user:admin",
    "revision": 7,
    "body": "## Overview\n\nLine 4 is the first north-south line of the Paris Metro, opened in 1908 between Châtelet and Porte de Clignancourt. It runs through the core of Paris and crosses the Seine River above ground between Cité and Saint-Michel [^wiki].\n\n## History\n\n- 1908: Châtelet–Porte de Clignancourt section opened; 1909: extended south to Porte d'Orléans;\n- 2013: extended to Mairie de Montrouge; 2022: extended to Bagneux–Lucie Aubrac;\n- Early 2020s: fully automated, using MP14 trains [^wiki].\n\n## Major Stations\n\nPorte de Clignancourt, [[place_paris_gare_du_nord|Paris North Station]], [[place_paris_gare_de_l_est|Paris East Station]], Strasbourg–Saint-Denis, Châtelet, Saint-Michel, Odéon, Saint-Germain-des-Prés, [[place_paris_gare_montparnasse|Paris Montparnasse Station]], Denfert-Rochereau, Porte d'Orléans, Mairie de Montrouge, Bagneux–Lucie Aubrac.\n\n## Operation\n\n- Operator: RATP [^ratp]\n- Rolling Stock: MP14 (rubber-tired), fully automated\n- Service Hours: approximately 5:30 AM–1:15 AM the next day",
    "url": "/concepts/paris-metro-line-4.html",
    "lang": "en",
    "availableLangs": [
      "zh",
      "de",
      "en",
      "fr",
      "ja",
      "ko"
    ],
    "conceptKind": "metro_line"
  },
  "entities": null,
  "mentions": [
    {
      "fromId": "concept_paris_metro",
      "fromTitle": "[{\"translations\":[{\"text\":\"Paris Metro\",\"to\":\"en\"}],\"usedLLM\":true,\"detectedLanguage\":{\"language\":\"zh-Hans\"}},{\"inputTransliteration\":\"Bali ditie\",\"script\":\"Latn\"}]",
      "fromUrl": "/en/concepts/paris-metro.html",
      "fromType": "concept"
    },
    {
      "fromId": "place_paris_gare_de_l_est",
      "fromTitle": "Paris East Station (Gare de l'Est)",
      "fromUrl": "/en/places/paris-gare-de-l-est.html",
      "fromType": "place"
    },
    {
      "fromId": "place_paris_gare_du_nord",
      "fromTitle": "Paris North Station (Gare du Nord)",
      "fromUrl": "/en/places/paris-gare-du-nord.html",
      "fromType": "place"
    },
    {
      "fromId": "place_paris_gare_montparnasse",
      "fromTitle": "Paris Montparnasse Station (Gare Montparnasse)",
      "fromUrl": "/en/places/paris-gare-montparnasse.html",
      "fromType": "place"
    }
  ],
  "lang": "en",
  "availableLangs": [
    "zh",
    "de",
    "en",
    "fr",
    "ja",
    "ko"
  ],
  "infoFields": [
    {
      "key": "concept_kind",
      "label": "Concept kind",
      "value": "Metro line"
    },
    {
      "key": "line_opened",
      "label": "Opened",
      "value": "April 21, 1908"
    },
    {
      "key": "line_length",
      "label": "Length",
      "value": "Approximately 14 kilometers"
    },
    {
      "key": "line_termini",
      "label": "Termini",
      "value": "Porte de Clignancourt ↔ Bagneux–Lucie Aubrac"
    },
    {
      "key": "line_structure",
      "label": "Structure",
      "value": "Underground (outdoor crossing over the Seine between Cité and Saint-Michel)"
    },
    {
      "key": "line_max_speed",
      "label": "Maximum speed",
      "value": "70 km/h"
    },
    {
      "key": "line_status",
      "label": "Status",
      "value": "In operation"
    },
    {
      "key": "line_operator",
      "label": "Operator",
      "value": "RATP"
    },
    {
      "key": "line_owner",
      "label": "Owner",
      "value": "RATP"
    },
    {
      "key": "line_rolling_stock",
      "label": "Rolling stock",
      "value": "MP14"
    }
  ],
  "pagination": {
    "page": 1,
    "pageSize": 50,
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    "pageCount": 0
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  "mentionsTotal": 4
}