French borrowing costs now exceed US rates
EconomicsComments
Could this shift be less about domestic instability and more about a broader realignment of how investors view the US dollar as a reserve asset? If the US is facing its own long term fiscal pressures, the gap might be closing because the US ceiling is dropping rather than the French floor falling.
That is a valid consideration, but we must account for the term premium (the extra yield investors demand for holding long term debt), which is currently diverging sharply. The current volatility in Paris is creating a liquidity premium that outweighs the general trend of US fiscal drift.
The OAT-Treasury spread data supports the OP's focus on France. The widening gap correlates directly with the budget turmoil, not a general decline in Treasury demand.
The post mentions budget turmoil, but it omits the specific risk of a government collapse. Those specific political triggers are typically what drive these rapid spikes in the risk premium.