Did German military men pay in French restaurants for their meals during the occupation in ww2?

Yes and no. Yes in the sense that money resp. an equivalent was handed over, no in the sense that this money was effectively paid for by the French state and the French people.

The Wehrmacht and the German leadership operated under the directive that all the costs incurred by the Wehrmacht and its individual members in a specific occupied territory were to be ultimately paid by said territory. So, f.ex. in occupied Polish territory, the General Government, the German government demanded an ever rising contribution to be paid as part of these compensations: In 1942 1.3 billion Złoty had to be paid, in 1943 3 billion Złoty and so forth while the Wehrmacht booked their own budget to be paid by the Poles as 100 million Złoty per month with the explicit purpose of financing the acquisition of foodstuffs for the Wehrmacht from that budget. Furthermore, the German government not only mandated that occupied territories pay for their occupation but also that they had to pay contributions, and had to take forced loans.

The Germans also manipulated the exchange rate between different currencies. In France where before the exchange rate had been 100 ffrs to 6.6 RM suddenly became 100 to 5. For German soldiers in France, their payment was paid in ffrs but calculated in RM in order to reduce inflation in the Reich and encourage spending in the occupied territories for exports from occupied countries could be calculated as cost of the occupation. This meant that German soldiers were encouraged to spend their ffrs in France, send goods to Germany, which the German government could book under exports from an occupied territory and therefore receive money again from occupied France.

In practice the system looked like this: Shortly after the Wehrmacht occupied a country, Wehrmacht soldiers at first payed in Reichskreditkassenscheinen (Reich Credit Bank Slips – RKK slips). There were RKK slips ranging from 0.50 to 50 RM and they looked like paper money but were not allowed to circulate in the Reich itself. What they basically served as were requisitioning slips for the idea behind them was that those receiving RKK slips as payments could exchange to ffrs at every bank. These banks then handed them over to the Banque de France in exhange for Francs. The Banque de France gave them to the German financial center in Paris but received no further compensation for their worth. The Banque de France therefore had to print money to be able to keep exchanging the RKK slips to normal ffrs. Basically, Germany exported inflation to occupied territories during the war since the RKK slips then were handed back to the Wehrmacht to be again given out to soldiers to spend on French goods and services. This way, services and goods purchased with RKK slips did not count as requisitioned or stolen by the Wehrmacht – it was a system that combined individual exploitation (paying under price, paying French forced laborers in RKK slips, requisitioning goods and services) with the regular currency circulation in France. This of course meant a huge, huge economic loss for the French economy.

In several countries such as Denmark and Norway, the practice of the RKK slips was ended, once an armistice was signed. But France was a bit of an exception to that. There, RKK slips continued to circulate for a variety of reasons but mainly because both for the German economy in the form of German companies and for individual German soldiers in France, the system satisfied a certain want for French goods. Richard Gruneberger mentions in his social history of Nazi Germany that during the Third Reich, German consumption of Champagne and sparkling wine rose a staggering 500% compared to Weimar. This is very much linked with the RKK slip system: German soldiers and companies could buy tons and tons of French of Champagne to send/export to Germany and pay virtually nothing for it while the Reich itself could book these exports as occupation costs. The problem became so endemic that in 1943 the Wehrmacht commander in France complained about the RKK slips and said that the system was not sustainable for much longer. In December 1943, the RKK slips were abolished in France because otherwise a total collapse of the ffrs and the French economy would have been likely.

In Western Europe further provisions were introduced to make life for the German soldier as cozy as possible: Restaurants and bars were prohibited from closing if German soldiers were among the guests, even if this went on beyond official closing time. The same for shops which sold items like clothing, coffee or luxury food. These had to remain open, even if not profitable, until German soldiers had been able to buy everything they had in store.

Practices such as this had disastrous consequences on an individual economic level and on a macro economic level. Not only were shop keepers and restaurant owners forced to operate under an economic loss for the sake of the German occupiers, the spending of the French state was essentially doubled due to having to pay war contributions and occupying costs to the Germans. Between 1941 and 1943 the French state effectively spend 250 billion ffrs annually, of that 29 million ffrs daily for paying the Wehrmacht. After liberation, the French finance ministry calculated that Germany had effectively robbed France of 900 billion ffrs during the occupation.

For the purpose of this question, this means that when German soldiers went to eat in a Restaurant in France and payed in RKK-slips, they virtually ate on cost of the French state and the French economy at large because while the owner of the restaurant could exchange that to ffrs at his local bank and the local bank could exchange them for ffrs at the Banque de France, the Banque de France then had to either print new ffrs or finance these exchanges with money from the French state budget. Effectively, it was the taxes of the French people who paid that food in a restaurant eaten by a German soldier.

So, they payed in the sense that money was exchanged for goods and services but that money ultimately came from the people who provided the goods and services.

Sources:

Adam Tooze: The Wages of Destruction.
Götz Aly: Hitler's Beneficiaries: Plunder, Racial War, and the Nazi Welfare State