Food Café is the Restopolis counter on the first floor of the Maison du Savoir, on the auditoires side. The Ministry’s own booking system gives its service window as 07:00 to 16:30, wide enough for a coffee before an early lecture and for something at the end of the afternoon.
What you pay depends on who you are, because Restopolis runs separate rates for learners, for university staff and for visitors.
The days are the one thing we cannot confirm. The Ministry’s system publishes the daily service window without saying which days it applies to, so read 07:00 to 16:30 as the shape of a teaching day and check the door during university holidays.
Food Lab is in the Maison des Sciences Humaines, while Food Lounge and Food Hub are both in the Terres Rouges tower. The whole campus network is covered in our University Restaurants entry.