The flag of French Guiana is not standardized, as it is an overseas department and region of France. The flag most commonly associated with French Guiana is the logo of the Regional Council, which is not an official flag.

However, in many contexts, the French national flag, known as the "Tricolore," is used to represent French Guiana. The Tricolore has the following characteristics:

1. Colors: Blue (#002395), white (#FFFFFF), and red (#ED2939).
2. Aspect ratio: 2:3.
3. Geometric properties: The flag consists of three vertical stripes of equal width, with blue on the hoist side, white in the center, and red on the fly side.

Since there's no standardized flag for French Guiana, the information you requested regarding color codes, aspect ratio, geometric properties, and measurements applies only to the French national flag.