I will go to France for honeymoon in mid-September.
I will stay in Paris for 10 days however, I need to stay for around 3 to 5 days in somewhere have beach or sea view so I thought for Nice, Cannes or Manaco (Monte Carlo).
I don't know where to stay, I'm thinking to stay the whole period in Nice and each day I go to another City or stay a night in each. I donno, can anyone help please!!

Take the TGV to St-Jean-de-Luz, about the same time as a train to Nice. This is a very cute town with a huge sandy beach. From Nice, the train goes along the coast; day trips are very easy, you don't need to move.

I think your ideas are basically okay, Ron has a good idea.

I hope you are aware the beach at Nice is not sandy so may not be what you envision. But you can find some nice hotels and good views.

Whatever you do, do NOT go and stay in new places every night. Have you ever done that in your life? If you have and love it, moving hotels every day, then you can ignore my advice. As long as your spouse-to-be thinks that is a fun idea for a honeymoon, also.

The weather in Nice is a LOT better/more predictable than the weather in St Jean de Luz - if that's important to you. We spent 2 weeks near St Jean in about 2003 and it rained quite a bit. We were there for 2 weeks in June 2013 and we only had about 3-4 days of "beach" weather. A guide book I have says that the Pays Basque gets more rain than Ireland - that's why it is so green.

Stu Dudley

I would agree to basing yourself in Nice and taking public transit to see a couple of the charming inland towns. I would not head to Monaco unless you like spending a LOT of money and watching the uber rich from their giant yachts in the harbor do the same at the many designer shops.

The Côte d'Azur will be beautiful in mid-September. The Atlantic coast may not be stable weather-wise.

Do not base yourself in Monaco - it is expensive and has hardly any beaches. You may go there for a daytrip but it is not a place to stay.

I would also not recommend to stay in Nice - it is a large city with an ugly beach, composed of large grey pebbles.

You find beautiful sandy beaches in Cannes, Antibes and Juan-les-Pins. These three towns have good public transport connections.

Cannes has a famous beach promenade with a row of luxury hotels (and a second row of less expensive hotels behind them). Cannes also has a charming old town and a yacht harbour.

Antibes is a historical town, also with a port, a castle, a museum with workds of Picasso and several coves with sandy beaches.

Juan-les-Pins is a typical seaside resort with a row of modern hotels along a wide sandy beach.

I vote for either Nice (crummy beach) or Antibes which has a really good vibe. Just stay in one place and zoom up and down the coast by bus, cheap and regular service. Have fun...