Brazeau, who has been suspended from the upper house, is to appear in court on Mar. 17.
Harb, who resigned from the Senate last summer, is due in court the following day.
Both are accused of defrauding the Senate of more than $5,000 by making false or misleading claims for living expenses.
Harb's lawyer, Sean May, says the former senator will be represented in court by his legal team and will not put in a personal appearance.
May said he expects the case will be adjourned for several weeks to give him time to pore over the Crown's evidence against Harb, which he expects to be disclosed soon.
Harb and Brazeau are accused of claiming expenses for a secondary residence in Ottawa, even though they lived primarily in the national capital region.
Both maintain they did nothing wrong and that the rules regarding primary and secondary residences are unclear.
Nevertheless, Harb has reimbursed the Senate for almost $232,000.
Brazeau was ordered last spring by the Senate to repay almost $50,000. He refused so the Senate garnisheed his salary until last November, when he was suspended without pay from the chamber.
Senators Mike Duffy and Pamela Wallin were also suspended without pay for allegedly making fraudulent expense claims. They are both still under RCMP investigation but no charges have been laid against either of them.
The RCMP is also investigating Nigel Wright, Prime Minister Stephen Harper's former chief of staff, who personally gave Duffy $90,000 to enable him to reimburse the Senate.