The scale of public expenditure to be incurred in the Covid-19 health crisis is raising heated debates about the appropriate funding. Long rejected by mainstream macroeconomics due to its possible inflationary consequences, monetization is currently undergoing a surprising rehabilitation. Financing public expenditure by money issuance - without the government ever reimbursing the central bank-, appears as an attractive solution in a context where the burden of public debt could become particularly problematic due both to the persistent threat of secular stagnation and the massive Covid-19 shock. This policy brief offers some theoretical insights into this debate opposing monetization and issuance of additional public debt.