Bijou is a female hamster owned by Maria, originally from France but now residing in Japan. She developed such a strong attachment to Japan that she refused to return to France. Fond of elegance, she cherishes her signature blue ribbons and maintains a preference for cleanliness and beauty. Despite this, she willingly gets dirty when necessary to assist friends, demonstrating her generous and helpful nature.

She possesses a somewhat naive personality yet remains deeply kind-hearted. Her most prominent emotional trait is her significant romantic affection for Hamtaro, the main protagonist hamster, with evidence suggesting these feelings become reciprocated in later developments. Another hamster, Boss, harbors a crush on Bijou, though she consistently directs her affection toward Hamtaro.

In the Japanese version, her speech includes the distinctive ending "dechuwa." Her name, meaning "jewel" in French, reflects her perceived preciousness.