This in in response to an entry which I had written in 2008 called 'Surnames from Place Names'. I tried to show how many surnames, especially from Southern Italy, had Lombard-inspired names. Recently while reading a book, and somewhat coincidently, I came across two similar type references. One French, and one Spanish.
Because the Langobards transgressed lands which were at least very close to France in ancient times, a French remnant is less surprising. The one example is a well-known street in Paris called "rue des Lombards," which is famous for hosting three of the main French jazz clubs: Le Baiser Salé, Le Duc des Lombards and the Sunset/Sunside. It was originally a banking center in medieval Paris, a trade dominated by Lombard merchants. Those "Lombard merchants" as well as "Lombard bankers" were actually not necessarily from Lombardy, but that name was used whether they were Venetian, Florentine, etc. In this example, the street wasn't specifically named after Langobards.
The Langobards and the Franks has a long history of friendship and intermarriage between the ruling families, long before the Franks moved west and conquered what is now France, the land which now bears it's name. It was similar to the Langobard invasion of the Italian peninsula. After conquering what became "Langbard," some Langobard factions invaded southern France, which began a long gradual process in which the two tribes drifted apart. This culminated with Charlemagne's invasion of Langbard, and the destruction of the kingdom.
In the other example, it's a Spanish surname called "Lomabardero." The origin could either be from "Lombard bankers/merchants" who may have set up shop in one of the larger Spanish cities, probably after 1492, or it could be from contact with the Langobards themselves. After the Moors conquered Spain, or most of it, they prepared to invade the Frankish Kingdom. Word was sent to the Langobard King calling for help. A Langobard army showed up just in time for a coming major Moorish assault. The Langobards had such a fearsome reputation that the Moors called off the invasion, as least temporarily.
Of course, there's always the possibility that an important individual might have been conducting trade with any other region and was given a name to match. Therefore, for example, a Spanish businessman of the Middle Ages might have been conducting overland trade with Lombardy.