The numbers could be a litmus test, correspondents say, after three of 12 national oil refineries voted to end their action and a rubbish collectors' strike in Marseille was suspended.
The row comes to a head this week.
Parliament is expected to hold a final vote on Wednesday, while a nationwide strike has been called for Thursday.
The vote in parliament is expected to bring into law an increase in the minimum retirement age from 60 to 62.
The BBC's Christian Fraser in Paris says the students are supposed to be on half-term break but instead are planning a series of marches around the country in opposition to the plan to increase the minimum retirement age.
President Nicolas Sarkozy will be hoping the vote - and the 10-day school holiday - will take the sting out of the protest.
But our correspondent says the students will be out to prove him wrong and how many come out will be the litmus test of where this protest is heading.
On Monday, all of France's 200 fuel supply depots were cleared of strikers.
And unions said that rubbish collectors in the southern port of Marseille would end their high-profile two-week strike on Tuesday.
However, our correspondent says that seven French refineries are still closed, buffer stocks of petrol and diesel are almost exhausted and unless refineries reopen, France could face an even more serious fuel crisis by the end of the week.
The government has warned that the disruption in threatening the country's fragile economic recovery.
Finance Minister Christine Lagarde said on Monday that the strikes were costing France up to 400m euros (£350m; $561m) a day.
The president says the reform is an "inevitable" measure in the face of France's rapidly ageing population and growing budget deficit.
His defence of the deeply unpopular reforms has seen his approval ratings plummet to a record low of 29%, according to a poll published last Sunday.
However, the vote in parliament is almost certain to pass.
An MP from Mr Sarkozy's party, Pierre Mehaignerie, said: "We must be aware that in a world without borders we can't have a French exception... that exists nowhere else."
But millions of people have come out on to the streets in a series of protests over the past few weeks and French trade unions have called another nationwide strike on Thursday.
That will be followed by yet another on 6 November, the unions say, unless Mr Sarkozy withdraws the pension law or opens negotiations.