eclair.conf

eclair.chain=mainnet
eclair.bitcoind.rpcport=8332
eclair.bitcoind.rpcuser=foo
eclair.bitcoind.rpcpassword=bar

bitcoin.conf

testnet=0
server=1
rpcuser=foo
rpcpassword=bar
rpcport=8332
txindex=1
zmqpubrawblock=tcp://127.0.0.1:29000
zmqpubrawtx=tcp://127.0.0.1:29000
addresstype=p2sh-segwit
deprecatedrpc=signrawtransaction