I didn't know about "The Basque Swastika" but I found this artcle that explains it quite well:
http://www.hollywoodreporter.com/review/basque-swastika-san-sebastian-review-636445"
The Basque Swastika is a rare film that looks at the Nazi
occupation of the Basque areas of France and Spain. Featuring interviews
with survivors and children of residents, as well as extensive newsreel
footage, the film opens a compelling window on Basque resistance and
cooperation with the Nazis"
well, the nazi occupation was mainly in the "french part" of the Basque Country, they occupied a small zone of the "spanish part" near the border and in the coastline but it was mainly the french part. As everywhere, there were some collaborators but it wasn't anything of significance. The same occupation wasn't anything of significance, for the nazis that was a lost part of Europe with no real meaning for them, not strategically, not in terms of population,.... so they didn't send too many forces here.
"The most intriguing element is the discovery of a short Nazi propaganda film called
In the Land of the Basques, which was made right in the middle of World War II by a favored German filmmaker, Herbert Brieger.
The question posed is why would the Nazis have spent valuable resources
creating this folksy tribute to Basque culture while the war was raging?
An answer is offered by several commentators, who suggest that the
Nazis viewed the Basques, despite their opposition to Franco, as one of
the “purer” races that might blend into the new Europe that they
envisioned after the war. The Basques were neither French nor Spanish,
so in the Nazi view, they were not tainted by the impurities of those
other cultures. Perhaps the Germans’ enthusiasm also grew out of their
discovery of swastika-like designs on some Basque pottery."
In every ancient cultures there are swastika-like symbols,.... better said, the swastika is like many ancient symbols, in fact, it's an indian religous symbol and it was taken by the nazis from there.
Here, in the Basque Country one of those ancient symbols is the "lauburu" which means four heads. There are more but the lauburu is the most known and used nowadays becoming the symbol of the Basque Country and its people