Is 150 Euro in my pocket enough to have 6 days food at Rennes city, France?
Of course I will prefer low budged food like bread, rice, biriyani, chicken or eag etc?
Rennes has four Lidls, https://www.lidl.fr. They all have bakeries.
150 euros buys you about 450 croissants, or about 25kg of tzatziki, or about the same amount of moussaka. In other words, you can eat about 4kg of moussaka every day for 150 euros in six days, without overshooting your budget.