Columbia subject headings:
Belgium--Foreign relations--France.
France--Foreign relations--Belgium.
Harvard subject headings:
Belgium--Foreign relations--France.
Belgium--Relations--France.
France--Foreign relations--Belgium.
France--Relations--Belgium.
Princeton subject headings:
Belgium--Foreign relations.--France.--19th century.
Belgium--Foreign relations.--France.--20th century.
Belgium--Foreign relations.--France.--21st century.