If you have at least 3-4 hours free time , you can take Taxi to paris .Don't waste time with RER (train) or bus etc . Make sure leave your heavy luggages with airport  concierge and calculate the « real » free time you have before being back in airport . 

You can visit famous monuments and walk in touristic center of Paris or even take double -decker bus tour etc ,  depending on  how much time you have .  
  
Taxi ride from center of Paris to CDG at late night or early morning will be about 35 minutes and in normal day time about 40-50 minutes ( still check the traffic condition and rush hour commute time ). 

There two major choice to go from Orly airport to disneyland Paris – Marne -la -Vallèe  :
RER trains or Taxis :


RER line B (suburban Train):
There is « RER B » that goes from the center of Paris to « Antony » train Station, there you have to take another special automated train named « Orlyval » to airport. The ticket cost 12-13 €. travel time is at least 35min. Train  intervals are 3-4 per hour. 


So you can come the same way back to Paris from Orly ,

Then in paris at «  Chatelet » Station , you get off the RER line B and take the RER line A to Disneyland in Marne -la -Vallee.

This trip may take easyly more than 1:30 hour . And ticket cost about 20 euros .

Taxis: 
Taxis can make the trip from  Orly airport to Disneyland in about 1 hour ,  depending  to time of the day and traffic condition, etc.  The taxi Fare is about 70 euros .

If you have a family or luggages with you trains and buses are not good choices , it will be difficult to carry all that through stairs and crowded trains , and train changes etc.. 
During the night or early morning taking a Taxi is recommended, rather than trains !  

Hi ,

To go from Paris to Orly airport or back to paris, you have few options;
Bus, RER, Shuttle and Taxis.
Orly is a smaller airport situated 12 Km south of Paris and comparing to CDG, doesn't have comfortable public transport connecting it to Paris. Orly has two terminals; south and west.

Notice; 

If you have a family or many luggages with you trains and buses for Orly are not a good choice for you, it will be difficult to carry all that through stairs and crowded trains, buses and changes etc.. 

RER line B (suburban Train):
There is « RER B » that goes from the center of Paris to « Antony » train Station, there you have to take another special automated train named « Orlyval » to airport. The ticket cost 12-13 €. travel time is at least 35min. Train  intervals are 3-4 per hour. 

RER Line C  (suburban train):
you can take RER C in Paris and make Sure you go to Direction of« Massy-Palaiseau ». Be careful, It can be quite confusing! If you look at the RER map you will understand. Get off at Station « Aeroporte d'Orly», then from the train station, take the special Bus to the Airport. Ticket price 6-7 euros. Travel time is about 1 hour .

Bus (Orly Bus): 
these are quite similar to normal city buses and not particularlycomfortable, you may not find a free place to sit. They go from Place Denfert – Rochereau 75014 Paris, directly to Orly airport. A ticket cost 6-7 euros. Travel time is more than half an hour.

Bus (Air France): 
These are more comfortable buses, they belong to  Air France company, and you will have individual seat.
They go from Place Denfert – Rochereau in Paris, directly to Orly airport. Ticket price 13-21 euros. 
Travel time about 1 hour. 

Shuttles (less good choice):
They pick up several people (up to 8) from different  locations in the City, and take them   to  the airport. It is very time consuming and if you are more than one person travelling together, taking a normal Taxi is much faster and more comfortable, without being necessarily more expensive.

Taxi: 
Taxis can make the trip from the center of Paris to Orly airport in about 35 min,  the Fare is 35- 30 euros, depending to your location.
If your more than one or having luggages or travelling in family tawi is a more convenient choice as well as economic one.

During the night or early morning taking a Taxi is recommended, rather than trains!  

To commute between Orly airport and CDG airport in paris you have 2 main options ;

Trains ( RER line B ) , Taxis .

RER line B (suburban Train):
There is « RER B » that goes from the center of Paris to « Antony » train Station, there you have to take another special automated train named « Orlyval » to airport. The ticket cost 12-13 €. travel time is at least 35min. Train  intervals are 3-4 per hour. 

Since RER line B almost connect two airports ;

So you can come the same way back to Paris and continue To the CDG airport, once you arrive in either « Chatelet » or « Gare de Nord » train station, make sure you be in right train for CDG! Not all RER B trains go to CDG. Travel time is about 75 min.

If you have a family or many luggages with you trains and buses for Orly are not a good choice for you, it will be difficult to carry all that through stairs and crowded trains, buses and changes etc.. 

Taxi; 
Is the easiest and surest way to commute between Orly and CDG,travel time is about 50 min (in normal traffic) and cost about 60€. 
During the night or early morning taking a Taxi is recommended, rather than trains ! 

To know more :

There are few choice of transportations for   CDG - Paris  :

Trains ( RER) and Bus services are available between center of Paris and CDG airport as well as Orly Airport .


RER train has only one station in CDG Terminal 2 , so in any  terminal your arrival ( or departure  ) is , you will need to go to the train station , and  CDG  is big . Ticket to paris cost about 10 euros and take at least 35 Min to arrive to center of city . The interval of trains is 3-4 train /hour .

There are few major inconveniences with RER ; first , if you have your family and luggages with you, carrying all that through airport and in side of crowded train and stairs, can be difficult.

second;  the train passes through some not very safe suburbs of paris and you really have watch your belongs and wallet etc .


Bus – there are two major bus lanes between CDG and paris , First is the normal City bus, and  ticket cost 11 euros , it is usually crowded and seldom you may find place to seat . Trip time from CDG  to paris is 1 hr.

The second bus lane is Air France Bus, in this one you will have individual seat and is quite similar to American « Greyhound Bus » . The ticket of this lane is 17 - 21 euros and trajet time to Paris center is 75 min .


Shuttles – the shuttles are the least good choice ! They take several people (up to 8) from different terminals and drop them off in different locations in city , it is very time consuming and if you are more than one person , taking normal taxi will cost about the same for you , beside taxi is much faster and more convenient .

Taxi -If you prefer to have more comfort and privacy you can take a normal Taxi ;

 These examples are based on parisian taxis  basic rate, fares can vary  according to the difference of rates in day and night , weekdays and holidays, time of day and  traffic conditions.   
   
   
 From   CDG - Charles de Gaulle  airport-  to center of Paris costs about 50 euros. Can take  from 45 min to 70 min depends to rush hour traffic.
in heavier traffic it will cost  up to 65 euros .
From CDG to Orly airport cost  60 euros , and takes about 55 minute .
 From Orly airport to center of Paris  costs about 30 euros . Can take from 35 min to 1 hr according to time of day and traffic.
 From center of Paris to Disneyland costs about 55 euros . Takes in average about 50 min time .
From CDG to Disneyland cost about 55 euros .  takes about 45 min.
 From center of Paris to Versailles palace costs about  35 euros. Takes in average about 35 min .
Average taxi ride within the city of paris costs between 10 - 15 euros.


To find out about rush hour traffic in paris  see my Paris taxis  page .