Answer:
Neither are entirely one religion (in this age the only countries without freedom of religion are almost all in the Middle East).
The French have been traditionally catholic and drove all of their Huguenots or French Protestants away when Louis XIV did away with the Edict of Nantes in 1685 which had allowed for freedom to choose to be Protestant or Catholic in France and was issued by Henry IV a Protestant king who was pressured into becoming Catholic and is famously quoted "Paris is well worth the masses". Driving away the Huguenots turned did not turn out well for the French as the Huguenots made up about 10% of their population and were very hardworking in general, forcing them to flee majorly hurt Frances economy and started the decline of France as Europe's foremost power. Today about 60% of the population remains catholic but only half of them truly are committed and consistently go to church. Another 30% are Atheist and a surprising 9% are Muslim due to large amounts of immigration from the Middle East. The last one percent are a mix of Protestants, Jews, and others.
Germany's religion has been very controversial throughout the ages. It was solely Catholic since the Middle Ages until Martin Luther, a German monk, started the Catholic Reformation with his written works of the flaws of the church and its corruption, most of northern Germany accompanied him in the transition to Protestantism; however southern Germany remained Catholic as it was closer to Rome and the center of Pope's power. This difference of religion caused the thirty years war (1618-1648) across central Europe. When King Ferdinand of the Holy Roman Empire (half Spanish and brought up in Spain and therefore Catholic) tried force religious unity on the Protestants of the country they did not take to it kindly and fought back in full force. The war was very destructive and is estimated to have killed about 1/3 of Germany's population until the Peace of Westphalia was signed in 1648. Today both Catholics and Protestants make up about 30% of Germany's population. The Muslims only are 2% of the population. Atheists are also very prominent and make up about 30% of the population as well while the last 8% is a combination of many other religions.