Paris, building by building

of 2,500,000 rivets · 26 Jan 1887

Paris, by the period it was built

2025

About the project

Paris, building by building

What you see

buildings from the register kept by APUR, the Paris urban planning agency. The colour shows the period each one was built in. They stand on the real ground, whose heights are exaggerated five times so the hills can be seen.

Hover over a building to see what is known about it. Click a building to select it, or click the street between buildings to select the street. A selection lights up on the map and on the timeline; for a street, the numbers in the legend count only its buildings. Click a selected street again, or use the button in its label, to see the buildings on both sides of it side by side, with house numbers and the names of known buildings. While something is selected, a click off the buildings clears it.

The search finds a building by name or address, or a street. The camera flies to it and slowly circles it. If a house number is not in the data, the search offers the nearest one on the same side of the street. Panorama puts you at street level in front of what you found.

Click a period in the legend to see it alone, and click it again to bring the others back. The timeline has two handles. Drag the right one to set the year shown. Drag the left one to start a range: buildings older than that year go dark, so what was built in between is easy to see.

How the dates work

APUR records a construction period for buildings and an exact year for of them. The periods here are APUR's own with two changes. The class 1851–1914 is split at 1870, to separate Baron Haussmann's rebuilding of Paris in the 1850s and 1860s from the decades that followed. The class before 1800 is split into five periods. The legend lists every period with its years.

A building with a period but no exact year gets an estimated year, taken from exactly dated buildings of the same period nearby. Of the buildings without an exact year, found such neighbours within 250 metres and more within a kilometre. found none and were placed evenly across their period. The hover marks all of these years as estimated.

Some dates come from a second source: Mérimée, the register of historic monuments kept by the Ministère de la Culture. It dates buildings here, where APUR gives only "before 1800", a round year, or a period that Mérimée contradicts. Mérimée dates a building's main phases of construction, which it calls campaigns, to the year or to a century or part of one, such as a half or a quarter. If it gives a year, that year is used. A century, or part of one, is spread across its span, as the register's approximate dates are spread across their periods. When several campaigns are listed, the earliest counts, unless APUR's own rough year points to another. On the timeline these buildings are drawn as small rings instead of dots, and the hover names the source.

Where the data is imprecise

Rounded years. More than half of the exact years end in zero, about five times more often than chance would give. On each round year we keep as exact only as many buildings as the neighbouring years would lead you to expect. The rest, which mostly mean "around then", are drawn faint and spread across their period.
Before 1800 the register gives half-century steps: 91% of those years end in zero. Read each of the five early periods as a rough range.
Estimated years. For buildings only the period is known. The year they appear at is our estimate within that period.
Monuments. Notre-Dame, the Sainte-Chapelle and the other medieval monuments have no year in the register, only "before 1800". Their dates come from Mérimée, usually to the century.
Rebuilt buildings. For some old buildings the register gives the period of a later rebuilding or restoration. The Hôtel de Sens, built between 1475 and 1519, is dated 1915–1939 in the register. Where Mérimée dates such a building, the map uses that date.
No year or period from APUR. buildings carry neither. BDNB, a national database built from French tax records, dates of them. It is a second source, the way Mérimée is, marked the same way on hover. The rest, buildings, take an estimate from their nearest exactly dated neighbours, as a period-only building does.
Only what survives. The register lists the buildings standing today. Demolished buildings are missing, including everything Haussmann cleared. The map shows when today's buildings were built. It does not show how fast the city grew.
Heights are APUR's median height for each building, measured across its roof. landmarks take their shape from OpenStreetMap volumes and are never set lower than APUR's own measurement.

The timeline

Time runs along a continuous axis from just before the oldest dated building. From 1600 on, each dot stands for 25 buildings of one period: one dot per building would need about twice the area of the strip, and the dots would merge. Before 1600, where few buildings survive, each dot is one building; a dashed line marks the change. Solid dots are buildings with an exact year from the register. Faint dots have an approximate date: either only the period is known, or the year is part of the register's excess of round numbers. They are spread across their period at the pace of that period's exactly dated buildings, so round numbers do not show up as bursts. Rings are buildings dated by Mérimée: bright for a year, faint for a century or part of one. In each column the solid dots sit at the bottom, the rings above them and the faint dots on top. The map uses the same dates. A few landmarks are named on the timeline.

Before 1600 the register rarely gives an exact year. A building with no year of its own, only the broad "before 1800" period, never appears before 1600 either: its estimate is spread across 1600 to 1799 instead, like any other approximate date. Only a real year, from APUR or from Mérimée, can place a building earlier than that.

Hover over a dot to light up its buildings on the map. Hover over a building on the map to see its dot ringed on the timeline.

Sources

APUR: Emprise bâtie Paris and Volumes bâtis (building footprints, volumes, construction periods and years). OpenStreetMap contributors, under the Open Database License: landmark volumes, building names, streets, the Seine and the city limit. Base Adresse Nationale, under the Licence Ouverte: house numbers. Mérimée, the register of historic monuments of the Ministère de la Culture, under the Licence Ouverte: construction dates of protected buildings. BDNB, the national building database compiled by CSTB, under the Licence Ouverte Etalab 2.0: construction years for buildings APUR's register leaves undated. Wikidata, under CC0: architects, and the links to articles and photographs. Wikipedia, under CC BY-SA 4.0: the short notes on buildings, quoted from their articles. Wikimedia Commons: the photographs, with each one's author and licence shown under it. IGN RGE ALTI, under the Licence Ouverte Etalab 2.0: the ground heights.

Alexander Bogachev · bogachev.fr · 2026