French President Francois Hollande's honeymoon with bond investors may be ending as economic reality bites.

Hollande, who returned from a 15-day summer break last week, faces an economy that hasn't grown in three quarters, rising joblessness, a ballooning trade deficit and the task of coming up with a plan in the next few weeks to plug a budget hole of more than 30 billion euros ($37 billion) for next year.

The challenges ahead may undermine the rally in French bonds that has allowed the country to sell bills at negative yields for the first time. During Hollande's first 100 days in office, the premium demanded to hold French 10-year debt rather than comparable German securities fell to the lowest in more than a year. That trend may be reversing.