Was there pressure to give French cruisers thicker belts?

Was there a significant effort to add more belt armor to French interwar cruisers?

Not decisively; designers retained role-based compromises, although later ships such as La Galissonnière achieved protection comparable to contemporary British cruisers.

There was no decisive push to sacrifice the intended design balance for a much thicker belt. French cruisers were not unusually fast beside their peers: the Suffren class was around 32 knots, Duguay-Trouin around 30, and La Galissonnière around 31 in service conditions. La Galissonnière's protection was comparable to a British Town-class cruiser. Later French designs therefore did move toward a more balanced result.