Prime Minister Manuel Valls presented the new text to unions and students' representatives in Paris in the latest of a marathon series of consultations on the measure which is aimed at freeing up the labour market.
Students were at the forefront of Wednesday's demonstrations.
In a significant change from the original text, Valls said small and medium-sized companies would not be able to unilaterally introduce flexible work practices into their working week.
The new proposals also strengthen the role of judges in rulings over redundancies.
Valls appealed for the unions to support the new measures which he said the Socialist government had modified after listening to the "questions and concerns" raised by the original text.
"I am calling for a new start," Valls said.
President Francois Hollande had acknowledged that the original text had required "corrections" and "explanations", but had firmly ruled out withdrawing the entire proposal.
"We need to reform. Yes, reform," Hollande said Monday.
The reform would remove some of the obstacles to laying off workers. Opponents fear it will erode the cast-iron job security that French workers on full-time contracts enjoy.
The government argues that it is trying to free up the job market and reduce unemployment, especially of young people.
But left-wing critics say it is another example of Hollande's government taking decisions more in tune with a right-wing agenda.
Two of the biggest unions, the CGT and the FO, and the largest student union, UNEF, were unimpressed by the changes and repeated their call for the entire draft reform to be withdrawn.
"If the government insists on going ahead with this reform, the people need to go into the streets," CGT leader Philippe Martinez said.