But the two former prime ministers disagree on how much to cut France's bloated civil service and on several other key domestic and foreign policy points.
FILLON: Proposes cutting 500,000 public sector jobs over five years and scrapping the 35-hour working week. Allow bosses and private sector workers to negotiate working time directly, within an EU limit of 48 hours a week. Require civil servants to work 39 hours a week.
Increase the minimum retirement age from 62 to 65 years. Cut corporation tax from 33 to 25 percent. Scrap a wealth tax on top earners. Cut public spending by 100 billion euros ($106 billion).
JUPPE: Cut 200,000-300,000 public sector jobs. Increase the working week from 35 hours to 39 hours for private sector workers but allow for flexibility. Require civil servants to work longer hours (number of hours not specified).
Cut public spending by 85-100 billion euros. Increase the minimum retirement age to 65. Scrap a wealth tax on top earners. Cut income tax by two billion euros.
FILLON: Reduce immigration to a "strict minimum" via quotas approved by parliament. Increase deportation of illegal migrants. Link development aid to Africa to commitments by countries to take back illegal immigrants.
FILLON: Strip jihadists who travelled to Syria or Iraq to fight alongside Islamic State of their nationality and bar them from returning to France. Allow municipal police to carry guns. Increase prison capacity by 16,000.
JUPPE: Arrest jihadists returning from Iraq or Syria. Place suspected Islamist radicals believed to pose a threat under house arrest. Increase prison capacity by 10,000.
FILLON: Introduce a national ban on full-body "burkini" Islamic swimsuits.
JUPPE: Opposes national burkini ban.
FILLON: Develop closer ties with Moscow. Lift sanctions imposed on Russia over its annexation of the Crimea peninsula. Bring Russia into the US-led anti-Islamic State coalition, along with Syrian President Bashar al-Assad's regime. Develop closer ties with Iran. Create a eurozone government to harmonise economic policy. Work towards a "Europe of nations" that "respects French sovereignty."
JUPPE: Critical of Russian bombardments of the Syrian city of Aleppo and its support for the Assad regime. Reform the EU to make it less bureaucratic. Strengthen European defence cooperation.
FILLON: Wants to amend a 2013 gay marriage law to prevent same-sex couples jointly adopting. Proposes making it harder for children born to foreign surrogate mothers to obtain French citizenship.
JUPPE: Would leave gay marriage and adoption untouched.