Geneva is about 3.4 times smaller than Sao Tome and Principe.

Sao Tome and Principe is approximately 964 sq km, while Geneva (including the canton) is approximately 282 sq km, making Geneva 29.25% the size of Sao Tome and Principe.
Tip: This to-scale comparison of Sao Tome and Principe vs. Geneva uses the Mercator projection, which distorts the size of regions near the poles.