Guinea-Bissau is about 4.6 times bigger than French Southern and Antarctic Lands.

French Southern and Antarctic Lands is approximately 7,829 sq km, while Guinea-Bissau is approximately 36,125 sq km, making Guinea-Bissau 361% larger than French Southern and Antarctic Lands.
Tip: This to-scale comparison of French Southern and Antarctic Lands vs. Guinea-Bissau uses the Mercator projection, which distorts the size of regions near the poles.
Compare further: Guinea-Bissau vs. French Southern and Antarctic Lands