France–Spain border

A peace signed on a river island

France and Spain made peace in the Treaty of the Pyrenees. The signing ceremonies were held on the Isle of Pheasants in the Bidasoa River, an island neither country claimed. The chief ministers, Jules Mazarin for France and Luis de Haro for Spain, signed on 7 November 1659.^[3] France gained Roussillon and part of Cerdagne, and Louis XIV gained the Pyrenees as his southern border. The two kings met on the island on 6 June 1660, and under the treaty Louis married the Spanish princess Marie-Thérèse.^[3]

The island is still shared. The 1856 border treaty declared that the island, also called the Île de la Conférence, belongs to France and Spain together.^[1] Under that treaty, as amended by a convention of 1901, France looks after it from 1 August to 31 January and Spain from 1 February to 31 July.^[6] The island is about 200 metres long, and visitors are allowed on it only on a very few occasions.^[7]

Three treaties from sea to sea

The 1659 treaty named the mountains but not every pass and pasture. By the 1850s, disputes kept breaking out along the line, because nobody was sure who owned certain land or which villagers had which old rights.^[1] France and Spain sent commissioners to read the old deeds and grazing agreements and hear from each village. The result was a treaty signed at Bayonne on 2 December 1856, covering the western end, from the mouth of the Bidasoa to the Analarra summit where Navarre and Aragon meet.^[1] It took full effect on 16 April 1859, after markers had been set along the line.^[1]

A second treaty, signed on 14 April 1862, carried the line east to Andorra. A third, signed on 26 May 1866, took it from Andorra to the Mediterranean, completing the border "from sea to sea".^[2] A Final Act of Delimitation followed on 11 July 1868, and the last treaty came into force on 7 March 1869.^[2] Today 602 stones or crosses mark the border, from Hendaye to Cerbère.^[4]

Where the Bidasoa forms the border, the line follows the middle of the river's main channel at low tide.^[1] The 1856 treaty also set up a joint inspection of the whole western line every August, carried out by representatives of the villages on each side.^[1]

“The Île des Faisans (Isla de los Faisanes), also known as the Île de la Conférence (Isla de la Conferencia), which has so many historical associations common to both nations, shall belong to France and Spain pro indiviso.”^[1]

Llívia, the town that stayed Spanish

The Treaty of the Pyrenees gave France 33 villages in Cerdagne, the high valley at the east end of the Pyrenees. Llívia was classed as a town, not a village, and Spain used that detail to keep it.^[5] The 1866 treaty was based on the treaty's article 42 and on a convention signed at Llívia in 1660, and it set out the perimeter of "the Spanish town of Llívia, enclaved in France".^[2] Today the enclave covers about 13 km² and has around 1,500 residents, who mostly speak Catalan.^[5]

The treaty let Spanish people travel freely through French land on the direct road between Llívia and Puigcerdà, crossing the Reur River on a bridge that belongs half to each country. French people could likewise use the roads across Llívia and Puigcerdà to get around French Cerdagne. Spain was barred from ever fortifying the town, and Llívia and the French village of Angoustrine share the water of the Angoustrine canal each week: the French from Sunday at sunrise until Wednesday at sunset, the Spanish for the rest of the week.^[2]

Shared pastures and a shared river

Herders had crossed the ridge for centuries. The 1856 treaty cancelled most of the old joint-grazing agreements, but kept two, between Cize and Saint-Jean-Pied-de-Port in France and the Aezcoa valley in Spain, and between Barétous and Roncal, based on rulings from 1556 and 1375.^[1] The people of France's Baïgorry valley were given permanent use of pastures on the Spanish side of the line in the Aldudes, and France agreed to pay a rent of 8,000 francs a year for them. Streams, springs and paths on the line were shared by both sides.^[1]

Water led to the border's best-known legal case. Lake Lanoux lies wholly in France, but it drains into the Carol, which crosses into Spain at Puigcerdà and joins the Segre.^[8] In the 1950s France planned to divert the lake's water to the Ariège to make electricity, and to send the same amount back to the Carol through a tunnel before the river reached Spain. Spain argued that the 1866 treaty and its additional act required its agreement first.^[8] An arbitral tribunal ruled in Geneva on 16 November 1957 that France would not be breaking the treaty by going ahead without Spain's prior agreement.^[8]

An open border, sometimes closed

Both countries are in the Schengen area, where there are normally no checks at internal borders. After the terrorist attacks of 2015, France brought back controls at its border with Spain, citing the Schengen Borders Code.^[9] In January 2021 France banned traffic at 13 crossing points. Most reopened by 30 October 2023, but the Banyuls and Manrell passes stayed shut.^[9] Those two, along with two smaller roads in Cerdagne, were reopened in June 2024.^[10]