The transition, though, is off to a halting start.

Mr. Macron wants to invest more than €15 million in programs to improve public and private retraining that have had only mixed success in recent years at ushering the jobless back into employment. Lawmakers won’t vote on the measures until the spring, and any improvements are expected to take months, if not years, to bear fruit.

That layoffs are being announced before this crucial part is done has fueled suspicion among organized labor. And while new jobs will eventually be created, many unions worry the changes are a ploy to strip away worker protections — and their own power. In the last several weeks, the country’s most ardent trade organizations have vigorously opposed such plans, with differing results.

The new rules tip the balance of power from workers to employers. Businesses have been reluctant to hire because it was difficult to shed workers. Employers have turned en masse to precarious short-term contracts to fill the gaps.

Now, companies will be able to negotiate job cuts and restructurings through voluntary departures directly with labor representatives inside the business, rather than under strict industrywide collective bargaining agreements. Multinationals can downsize loss-making French operations more easily, even if the overall business is profitable. Companies will face less risk of legal action over dismissals, and can hire new staff immediately, rather than waiting.

The government has portrayed the changes as continuing to protect workers. When Pimkie, a struggling fast-fashion chain whose parent company is profitable, sought hundreds of voluntary buyouts, unions and workers rejected the proposal as insufficient. Managers must now go back to the negotiating table until payout terms satisfactory to the unions are reached. And unions will negotiate with management over the terms of at least 2,500 voluntary departures being pushed by the retail giant Carrefour.

Yet the measures clearly give companies more flexibility. PSA Group, which makes Peugeot and Citroën cars, will offer 1,300 voluntary buyouts to older workers. It will fill most of those vacancies with younger, less expensive employees on full-time contracts after most unions approved the plan, originally unveiled last year. PSA will also offer 2,000 low-paid apprenticeships to young people.