A bare majority voted in a referendum on Sunday to cut immigration quotas and require that Swiss nationals be given priority in hiring. The result could have far-reaching implications for relations between Switzerland and the 28-member European Union, of which it is not a member.

Laurent Fabius, France’s foreign minister, said Monday that the European Union would have to reconsider its relationship with Switzerland.

“It is a vote that causes concern because it means that Switzerland wants to withdraw into itself,” Mr. Fabius told RTL radio.

Viviane Reding, vice president of the European Commission, the executive arm of the European Union, told the BBC that Switzerland could not “pick and choose” among its agreements with the bloc, adding, “it is a whole package they have signed up to.” She said that the Swiss government must now explain how it intends to apply the results of the referendum.