What larger guns would change for French cruisers

How different would French cruisers be with 6.5-inch light-cruiser guns and 9.4-inch heavy-cruiser guns?

The light cruisers would change little, but the 9.4-inch heavy cruisers would be substantially more dangerous.

Moving French light cruisers from 6-inch to 6.5-inch guns would not fundamentally alter their role or combat behavior. The change remains close to existing light-cruiser practice and preserves a similar rate-of-fire problem. A shift from 8-inch to 9.4-inch guns is more consequential. Those heavy cruisers would become markedly more threatening to contemporary cruiser armor and could help trigger larger-caliber responses abroad.