The text recounts the problems experienced by the French soccer team in the World Cup including tempers and refusals to practice. The tensions on the French soccer team reflect a deeply held perspective on what being ""French"" really means and is a window into the problems that surround what concept?

Ethnicity

Explanation:

Ethnicity is the term used when a classification of people who share a common idea of ancestral and cultural connection among them and who considers themselves to be a distinct group of people from the other groups.

Thus by referring to "French" soccer team, we mean people belonging to the country of France, who have and share the common nationality and cultural beliefs.

Thus the answer is "Ethnicity".